You're never too old, for BMX. I don't go there too often these days, but if I'm remembering right, there was a guy over at Vintage BMX who was in his 40s and just started learning flatland within the last few years.

I'm 34, and regularly ride my BMX around on mountain bike trails. Maybe I look foolish, but I'm having way too much fun to care.

Can't help you on the wheels, I'm afraid. I always paid more attention to race stuff.