Sorry to say but it's different for everyone. There are different factors that determine how long its going to take: insurance, health issues, surgeon, etc.
I personally when to a seminar in February and my surgery is set for June 14th, but I could have had it in May if I wanted. I wanted to wait until I was out of school so I chose June 14.
My insurance required a supervised diet for 3 months and to see a psychologist. I had to go to my PCP once during February, March, and April. She faxed some documentation that I was trying to lose weight and I saw a psychologist once.
I've read in other posts that some people have had to wait 6 months and have more testing done.
My surgeons assistant was very knowledgeable about what my insurance required and had it all ready for me. I just followed what she requested.
I've also read that some people have met with their surgeons multiple times and I have only met with him for my consultation and my pre-op appointment.
Sorry this is probably not what you wanted to hear, but there is no definitive time line.
Good luck to you, though.