Well I'm 10 and I had a boyfriend last year but not rlly we just both liked each other I think between 12-14 or when they just find somebody they love! And want to be with all the TIME
It feels like you are free but it can be scary when you first get on but after a couple rides you will love it if you do it right! Dont worry
I think that they should when they are ready not just because there friends do so they can fit in I mean there is no point unless you need it!