Lol, I feel ya man, but honestly there's no need to post this but since you did here's two things that helped my confidence while I watched 13 year olds hitting backflips off little kickers:
1. Wear knee pads, elbow pads. Not because you're actually gonna hurt yourself hitting boxes, but it gives you more confidence that you're not gonna fuck up your knee on an embarrassing little fall. Also, if your gear is baggy enough no one can even tell. I wore them for a bit and honestly never even need them, but helped me hit bigger things.
2. Go early in the AM, on the weekdays when no one is around. No one is around to "judge" you, not that anyone cares anyways. Go slow, who cares if you stop midway on a box and have to step off it. If a tree falls in a forest and no one hears...