Forget the sportbikes, cruisers, or any street motorcycle. If you want to live long and learn how to cope with all sorts of challenges, go dirt! Get a small (XR200 for example) dirt bike in fairly good mechanical shape, somewhat beat-up with a low price to match. Find an area to ride like your local motocross facility and do your crashing and bike wrestling in soft, rock-free dirt! At most local (small town) mx tracks they offer lessons and two hour practice sessions for like $25. If you are nervous about looking like a fool find other beginners or whatever your skill level and get a group rate. Those small arenas need to make money to stay in buisiness and it is a big plus for them to have some income when the track wouldn't be used. You will develop skills faster than any other venue I can think of. You might even end up doing some novice racing. Go see some of the regular races there are all levels represented and some ride slow enough that you could just about walk faster than they are racing! There are quite a number of little girls and young women getting into MX these days. Good luck!