Colin----How old are you?
The one thing I can really say is I highly suggest you wear a helmet. Personally I dont wear a helmet, but if I know Im going to the park that day I always put it on. Your playing around in your back yard, going into trees and jumping over little kickers into the street. And your riding over little man made rails. It looks like you just found stuff in your yard and put it together. Which is great. Awesome. But damn man, put a helmet on for real. You look really young.
I dont mean to play the role of mother here, but Im just sayin....