I do SO wish you were in Minnesota.
A good rider can handle any bike. It doesn't matter that you're a girl, or 19, or 100 pounds. What matters is that you are in control of the bike, and not the other way around. You could drive a 600 pound bike if you know what you're doing. Which leads me to . . .
Take the safety course. It is a great education for people who've never been on a bike, and it's a great education for experienced riders. Everyone has something to learn. They will talk about gear, and you can talk to people there about different bikes.
Take the safety course before you buy a bike. You've probably been eyeing the dealerships and classified ads. You're going to see a bike that looks perfect for you. Don't buy it. Take the course first.
The Ninja 250 is a great bike. It's very light (304 lbs dry), so you'll have an easier time with it if it starts to lean over. And it will be easier to pick up after it falls over. Plus they are cheap new and dirt cheap used. And insurance is cheap for them, too. You'll save so much money on the bike that you can spend all you want on gear. Which leads me to . . .
Get good gear. Everyone knows you need a helmet, jacket, gloves, and boots.
If you forget everything else I say, remember this one word: "leather." Young girls (okay, 19 is young to me) have sexy, soft, beautiful skin. Road rash really ruins the moment, if you know what I mean. Chopped up skin looks bad enough on a guy. Don't let it happen to you. It would make me cry.
In Orlando you probably want perforated leather, because it's so stinking hot down there. I was there in April and it was hot enough then for this Minnesota boy.
A good leather jacket and pants will cost you a lot of money. Spend the money. If you don't have the money for the leather yet, don't buy the bike. I'll catch some flak for that statement, but that's my advice. If you can afford the jacket, but not the pants, don't buy the bike. How do you think your gorgeous legs are going to look after you grind one of them on the asphalt? Get the leather.
I'll get off my soapbox now. You can call me a male chauvinist pig if you want to, but you girls are so good looking I just hate to let anything interfere with that. Now a 19 year old girl on a sportbike, and wearing leather . . . ooo, ooo, OW! That's hot!
Curt