Mma fighting

I've been doing muay thai kickboxing and ju jitsu for aome time , im under 18 how would I sign up so that I can start full on matches not sparring

Depends on where you live what camps are close. Plus MMA is huge right now you might want to spar practice as much as possible before entering the grinder. I'm a big fan of MMA wanted to train myself at one time. Hope you do well man maybe I'll see you on TV.

probably the best way is by joining a gym that has an mma camp like chute box, american top team, militech, greg jacksons camp etc.

I do MMA myself, I was in the european semi-finals, so what I did was practice my kickboxing a lot, then try your local gym for applications, lucky for me my barber is my MMA constructor.. lol
but you really need 2 practice 1st man...