Bariatric Surgery Exchange

I am 21 years old, 313 lbs, and 5'6". I have begun my 6 month assessment leading up to the gastric sleeve surgery. I was going to do the lap band but my doctor thinks a more aggressive option is going to work better long term for me. I have already lost 13 lbs on my own due to diet change and exercise, and I plan on keeping it up before, through, and after the surgery. I hear stories of women my age and size (age being a factor with a faster metabolism) losing 100+ lbs in 6 months or less. I am 313, to be under 200 lbs... I tear up at the THOUGHT of it. I am walking down the isle in June of 2013 (not the reason I'm having this surgery, just an added inspiration) and I don't even know if my fiance will recognize me at 200 lbs. I need some sort of support going into this surgery, advice on how to let food go, on how to stay motivated, on how to ignore the haters that seem to think that I had this surgery for "cosmetic reasons". Of course it's cosmetic!!! I don't WANT to look like this anymore, but I also have extremely high cholesteral, thyroid functions, blood pressure, and polysystic ovarian syndrome (which could disappear with weight loss). I have tried options on my own, I have lost 14 lbs in 4 months. But with so much weight on, it hurts to walk, it hurts to exercise, my chest tenses up and I fear heatattacks. I do walk, every night, with my dog. But this surgery will HELP me change my lifestyle, I know it won't change my lifestyle for me. I have to be willing to change too. This I all know, but I need some support to assure me that I'm not taking the easy way out. That I'm not "too weak" to lose the weight without surgery.