one- both those guys have been in the scene for awhile- west was like 17 or 18 when he started getting big.
chug has been sponsored and around NS for at least five years(probably closer to 7 or 8), only really making the switch to "pro" in the last year or two (pro consisting of making a decent wage... two years ago cosco was asking kids to sign up for COC or HN so that he could have a summer job.)
turpin entered the sport as not only a gifted athlete but also at a time where switch 7's were winning x-games gold... sure he was 21, but it was ten years ago and the level of competition was completely different.
I hate to break it to you, but hoping to launch at career after twenty seems unlikely in a sport ruled by youth.