Question about mma fights?

im 16 n ive bn doing mma for about 2 months n i was jw how well expierenced you have to be b4 you have your first fight im a pretty good fighter...i use to box for 4 years so i have good striking any help? i was also told that for actuall mma fights you have to be 18 is that true is just some bs someone was telling me?