My name's Sebastian and I'll be turning 28 in a month. Yeah, I know this is for the over 30 crowd but if you could cut me a little slack, I'd be greatly obliged. I'm crazy out of shape but am completely captivated by this.
Whippersnapper!
No, seriously, welcome. We don't get as much action on this board as is, so I'm sure glad to see you.
Two things I've learned doing parkour as an older guy (I'm 46, started about 1.5 years ago):
1) My tendons got strong a lot slower than my muscles. That is to say, I did damage to my tendons because I was so surprised at my muscular gains. Really work on learning how to do landings very well before you try to do any real drops or even land from vaults. Do some eccentric squat work to strengthen your patellar tendons. You'll regret it if you don't strengthen them.
2) Repetition and consistency are key. Don't be disappointed if you spend an entire practice session doing something very simple over and over. Then next time, that move will be easier. And one day it will be second nature. Don't rush it, but *do* be consistent about working out. The quickest way to get injured is to only work out once a week and then try to jam everything into the practice session.
Good luck! You're going to do great!