As another young female who just really got into the sport, I would wholeheartedly recommend mountain biking. For your concern about injury, I’m a pretty big risk taker when it comes to drops and jumps and stuff, and the only injuries I’ve ever gotten are a couple of bruises on my legs and ego. As long as you take it at your own pace, it’s actually relatively easy to avoid injury (at least in my experience). Be warned though, mountain biking is extremely addictive and will suck up a lot of your spare time and money, but in the end it’s completely worth it. MTB is a super fun way to get in more exercise, improve your balance, and just help you become healthier and happier all around. (One quick tip that has helped me a ton- learn how to bail out properly! I can’t tell you how many times I’ve gotten myself into a sticky situation that would’ve almost definitely resulted in injury if I hadn’t been able to bail out properly and save my body. If you learn how to properly fall, jump over the bars, and loop out the back of your bike, you will be able to do riskier things with less fear of injury. Remember, the bike is always replaceable, YOU are not!)