Hi clockworkbuddha,
I can relate very well to how you feel, I was in the same position as you although I'm 9 years older than you now. My big shove towards making my decision was starting to get heart palpitations and whilst nothing was found wrong despite a barrage of tests it was enough to send me down the surgery route as the various diets and tablets weren't working.
As for preparing psychologically for my surgery, as part of my "package" I got to have a number of appointments with a councillor to discuss any fears or anxieties and to make sure I was ready for a life style change. I was prepared very easily after hearing the results of the cardiac MRI I had whilst trying to diagnose my heart palpitations. I had/have a fatty heart as a result of my weight and the only way to lose it was to lose weight. Either that or realistically expect a shorter life span. That was the kick up the backside I needed and put me in the right frame of mind and made me determined to see it through - you are a long time dead as they say and it's not my time yet so I'm not going to give up that easy.
I can't really give you any tips or advice in getting in the right place psychologically because everyone will have their own reasons for doing it. I had my sleeve on the 10th of June and although it's still early days - I'm loving it, the weight is going, my knees no longer hurt when walking and I don't get breathless climbing just one set of stairs. I'm so glad I made the decision to have it done.
The hardest bit of the entire process for me wasn't the surgery or the pre-op diet, my provider had a number of options and I did Heinz Weight Watcher soups and Muller light yoghurts for 2 weeks. OK it got a bit boring and I was combining different soups together and adding various herbs and spices to make it more interesting. After surgery I had to do 2 weeks on liquids, then 2 weeks on pureed food followed by 2 weeks on soft foods before back to normal foods. The hardest bit was pureed food for me, I hated it, but it was only 2 weeks out of what I sincerely hope is going to be a longer life than I could have realistically looked forward to prior to making my decision to have surgery.
I really hope you get yourself in the place your head needs to be and when you're there embrace the experience and look forward to a new healthier, lighter you and a longer life to come.
All the very best.
AE.