I would say do research, research, research and write down a list of any resulting unanswered questions as the first appointment with your surgeon might be overwhelming for many reasons. Listen to their advice re which procedure they advise you to have (this is one time in life when someone of their experience will know better than you), and do not ignore or contradict any instructions given by them. And finally for WLS to work your head has to be totally in the zone and as Paula has said you need to start work putting it there from the second the journey starts - for me that was the day I made the decision to go for surgery. I had supported my best friend through his bypass eight years ago (was with him through his six years on the w/list, walked down to theatre with him, and was in HDU waiting when he returned, and every step of the way after) and despite all my experience and research, NOTHING prepared me for how challenging the first weeks after the bypass were going to be. You will be saying goodbye to your best friend and worst enemy, and your body post-op will not allow any negotiation. Stick to your pre-op liver shrinking diet like glue.
I am nearly 5 months post bypass and have been obese since a toddler (am now 50). I now eat a wide range of foods just not much of them. I have lost 5.5stone - in real terms size 22/24 to 16. I could not be happier.
Welcome to the forum, and good luck with whatever you decide. If it's a bypass then from experience I can say you will not regret it x
Just editing to add that I see you are having a bypass - hurrah!! xx