hi, im a fairly new member to bmxing, and new to this forum. i jsut got a newer bmx bike yesterday, that was 20 inch because my old one was about to crack in half, and i was wondering something. after a day of doing some bunny hops, and some flatland, i realsized then when not standing on the pedals, and sitting, the bike was small. are all bmx bikes size 20 universal? like, is that what most people use even if there taller than me? im 5.7-5.8 . thanks.