My two cents
I was in your position about 2.5 years ago. Never had ridden a bike except for a couple of times on a small dirt bike when I was a teen. I'm 60 now and currently have four and a half bikes (I own a nice sportster with a friend that we bought just to sell and that accounts for the half, lol). I have 3 here in Colorado and one in New Zealand. All very different bikes, but I love them all. I'm getting ahead of myself though.
It all started with a younger friend of mine who borrowed a bike for a Sunday ride after not riding for 9 years. He gave me a call on the following Monday morning and bought a new Harley Softail Slim. He's impulsive like that and has more money and someone in their mid 30's should have, lol. A couple of months later I got a call from him: "You HAVE to buy a bike." He is the guys who always knows a guy that knows a guy and this time he new a former collage football player who knew a retired pro player who owned a vacation home in Sturgis. The guy farmed and harvest was late so he couldn't use his house. He told his friend to come up and use it and bring all his friends.
Soooooo...... I signed up for a motorcycle class and got my license. Since we were going to Sturgis I had to have an American V Twin of course. I knew I'd immediately out grow a Sportster. Found a great deal on a 2003 Victory v92c. Pretty big bike, but nice, low seat height and it fit me well. I didn't really feel competent to ride it home 80 miles so my friend did. For several days I went by myself and rode around two huge, mostly unused parking lots that were connected by a long driveway going up a pretty steep hill. I practiced figure 8s, stopping, starting, starting from a stop on the hill and going up, shifting up and down until it became automatic. I did this sometimes for 3 hours straight. One I felt good there then took to small town streets and hit every stop sign, stop light, and intersection I could. After a few days of that I then started driving the highways between small towns (with more intersection practice in each town). When I felt good there I started driving the interstates in Denver (I live in Boulder and play hockey twice a week in Denver so that was a good way to combine riding with my normal routine). So after three weeks of riding the snot out of my Victory I went off to Sturgis. With my hi viz yellow helmet and airbag vest on my 'hi viz Skittle green Victory', lol. What a cool trip. It was the 75th Anniverary - just packed with people and bikes.
I say get a bike that will last you awhile. Get a used one. There are lots of very nice older ones with low miles that have been depreciated a bunch. I wanted to get something like a Suzuki C50. Those are pretty bullet proof and can be had for about $3,000 - 3500 out here. My peer group all had Harley's and would only have Harley. They found a Victory to be merely 'acceptable', lol. I got my Victory for only $3K because it had a pretty ugly paint job - paint was nice, but the color and graphics were, ah, err an acquired tasted. I've repainted it a nice satin grey now and will sell it for more than I paid for it. It has only 10K miles on it.
Also I have found that you need to 'ride your own ride' when with a group. I didn't know there was even a phrase for it. I just did it naturally. If you aren't keeping up with the herd then don't sweat it. Just ride at a pace that you are comfortable with and know where you are stopping (it helps to have a Hi Viz yellow helmet though so all your buddies can keep track of you, lol).
So in summary:
1) Ride the snot out of whatever you get and ride it slow. Don't progress to harder stuff until you are comfortable. Any idiot can ride in a straight line and do so very, very fast. It's the curves that will get you! The other thing that will get you, but not from an injury standpoint, is stopping, starting and slow speed maneuvering. Not injury, but it can critically wound your pride if you drop your bike in front of an audience, lol.
2) Buy a used bike. Motorcycles like, rvs, depreciate like mad the the first few years and many get little use. They are prefect things to buy used. You'll want a different one or one's after you have ridden some. It's a given. You need to find out what type of riding you want to do and then find a bike or bikes to to fit that riding. (I had no idea I'd want to ride two up until my current girlfriend was game to try. She had never ridden either. We went to Sturgis for the 76th as her first real trip. One of the guys left early and we got to use his Street Glide for a day. I immediately knew my Victory Cruiser's days were numbered!) Buy yours in the winter and sell yours in the spring. I have no idea why people and dealers sell bikes at such a discount in the winter. I bought a new 2013 V Strom Thanksgiving 2015 (last new one in the country that I could see on Cycletrader and it happened to be in Denver). I can still sell it for more than I paid, but it is a keeper. It's surprisingly roomy and comfortable for two up, especially with the bigger windshield I put on it. I got a 2008 Victory Vision a couple of days before Christmas (remember I said the Crusier's days were numbered). It had 22k miles on it and is in excellent condition. Two owner and ridden very gently. I just wore out the original front tire! I stole it for $5,700. I knew I wanted a Vision and just kept watching craigslist. I worked the guy down from 7,500 to 5,700 and 7,500 would have been a really good deal. Love this bike, but like my Vstrom better for running around town. I bought a 2008 Suzuki Bandit 1250s in New Zealand. Love that bike too. The power and torque have really spoiled me. That one had 19K miles on it when I got it, but we put 4K miles on it in 2.5 weeks on our trip in February. These are bulletproof bikes two. I bit tight for two up, but OK. I just wanted a bike with full cases that I could resell after we used it for about what I paid for it and it fit the bill. We have two more trips there in the next 10 months. Bikes are expensive to rent so after 3 trips I can pretty much throw it away and still come out ahead. Fortunately I have a friend in NZ and I can keep a bike there. What I'm saying is that it is fun to try out a variety of bikes. They are all so different and much less expensive than cars. You should try a bunch of them. I know the Vision is a keeper, but I'm tempted to replace the Vstrom with a Bandit now, but then again maybe something else would be fun!
3) Ride your own ride. I don't need to go fast to have fun, but some people do. Before you know it you'll be fast enough to keep up with everyone.
I jokingly said my 5 riding priorities were:
1) Don't fall off the bike.
2) Don't fall off the bike.
3) Don't fall off the bike.
4) Have fun.
5) Try to keep up with Don (the friend who got me into riding)
After our NZ trip I modified number 3. It's now: Don't scare Suzy"
4) Finally, be safe. When I decided I buy a bike and learn to ride I joking said I get an airbag if they made ones for motorcycle. for some reason I googled it and lo and behold there WERE airbag vests and jackets available. The Japanese invented them for construction workers in case they fell from a height and then realized they would work for equestrian sports, and bikers. I have a vest that the Toyko police use. It's a very simple device that is tethered to the bike and inflates via a co2 cartridge if there is enough force on the tether (don't worry you can't give it enough force by forgetting to unhook before you get off the bike). My girlfriend and I always ride with full helmets, boots, armored jackets and pants, and the airbags. We joke that we put on just enough gear to almost take the fun out of biking and there is some truth to that. None of my friends would be caught dead in an airbag vest or even a hi viz helmet. Many times they ride in half helmets and jeans. Hell, when we go to Sturgis even the half helmets come off so they can look like real bikers in their leather vests and bandanas on there heads (you'd never know one is a real estate developer and other is a CEO for a defense contractor, lol.) It's damn nice to live in free country, but you'll have to pry my airbag vest from my cold dead fingers.