Just find the nearest combat gym in your area. Don't buy into the whole "MMA Class" gimick. Legit gyms will have a free trial or a free class that lets you check out their program. Wat I suggest is that you train BJJ, Muay Thai, and Wrestling sperately or BJJ, Muay Thai and "MMA"
After a few months your trainers will let you know if your ready for a fight. I would personally wait 6 months to 1 year but I guess I am just cautious.
So I hope that answers your question, go start training ASAP and drop the excuses that I hear everytime; "Oh I am going to get into shape first before I go to the gym." No, just no. Even BJJ will kick your ass I can bet you that. The whole point of training is to get you in shape and teach you the techniques.
Goodluck and enjoy