I'm sure your doubt is quite common--nothing we have ever done has been successful (for the long run) and so we all feel this is a goal we can't ever accomplish!
I'm 60 years old and going to be banded next month--and all I know is that this seems to be our very best option for permanent weight loss. All we have to do is to follow the rules--if you've been reading the lap band forums on the net, you know what the consequences of not following the rules.
Perhaps this is our true answer--all I can say is that I'm going to go for it--because without it, we are doomed to a lifetime of being overweight and all the 'baggage' that goes with it from ourselves and society, not including the eventual severe health issues, i.e. diabetes, kidney disease, congestive heart failure, knee and hip replacements.
Don't doubt yourself any longer--all these people did it, and we sure can too!!