I have trained in No-Gi Jui-Jitsu, Muay Thai, and Submission Grappling for several years. I also have several amateur fights under my belt, and was considering a move to pro. But, I've been out of the gym since I blew my knee out, and have no money to get surgery on it. I still stop by once in a while to do some light striking work, and help out a couple of the guys with instruction, but no way can I roll on a bum knee. My school is the only real MMA school in this area, but it's far from a McDojo, with our lead Muay Thai instructors being Cedric Swyzer, Glen Cordoza and Erich Krauss. Glen and Erich both handle advanced Muay Thai, and together make up Victory books. They have helped co-write almost all of the MMA books out there, including books with BJ Penn, Fedor, Anderson Silva, Randy Couture, the Nogs, Karo Parisyan, Matt Lindland, Eddie Bravo, etc. Cedric won the European Kickboxing middleweight title before he moved here, originally from Switzerland. Our head No-Gi/Submission Grappling trainer is Jason Pietz, formerly of the Lion's Den. It's also an AKA affiliate. The head BJJ instructor is Ira Daugherty, who is a brown belt under Saulo Riberio, but he didn't come to us until after I got hurt, so I've never worked with him.
I started Jui-Jitsu at a McDojo when I was about 15 and living in Texas. Started it as a hobby, I was interested in Karate, did some research and realized that jitz would be better suited for my physique. Fell in love with it, and continued my training when I moved back to California. Started MT two years later, under Seth Weil (Rob Kaman trained), fell in love with that too. Soon thereafter, I heard from a couple friends in the fighting game that Jason and Cedric were opening a MMA school here in town, and was among the first few to sign up. Trained with them for about 3 months before I had my first amateur fight.
I was training for quite a while before I had my first fight. I went in there and destroyed everybody I fought, amassing a 6-0 amateur record. I was fighting guys from generation tuf who had been training for a couple weeks, while I had years under my belt.
My point is, don't rush yourself. Don't go in there under-prepared. Don't decide to go in for your first fight if you're uncomfortable with the idea. But most of all, take the time to find a good school with good trainers. That will make a world of difference. Any school can slap "MMA" on their sign. I had years of experience before my first fight, and I think that is what led to me doing well. Exact time frames vary person to person. One guy might need a year before his first fight, another guy might need a month. It all depends upon how fast you learn, how well your instructors are teaching you, and how soon you're comfortable fighting. Take it slow, and when you feel like you're ready, you'll be ready. As far as cutting weight goes, I've never had to lose more than 5 pounds to make 135. I'm 5'10, and would walk around at 140-145 while I was training 3 days a week. Right now I've been out for a little over a year, and am walking around at around 150-155. For 6'4", I wouldn't cut under 185. Any lower than that, and you'll be sacrificing muscle mass.