Is it normal for a 12 year old to have a wet dream Every night?

Wet dreams like most things connected with puberty vary from boy to boy. Some boys never have a wet dream while others (like yourself) have them frequently. If you would like to reduce their frequency you could try masturbating just before you go to sleep as this will use up the stored semen, which will then take a few hours for your body to replace. If you sleep naked then wearing pyjamas or underwear might help to prevent your penis from rubbing against the bed clothes and stimulating you to orgasm.