I'll agree about the part of gaining confidence about it. It takes a time of adaptation and confronting the anxieties linked to the bag. I guess that the sooner you face things you are afraid of might be the better (unless you are in a situation where you know you have been dealing with too frequent leaking obviously).
Once you will have gain confidence with your appliance's change and reach the point where your stool has adapt (get firmer cause at the beginning it's liquidish and not behaving and it makes noises for a few weeks/months). Don't wait too long thinking you can't do things because of the bag. Go on a camping trip, go hike, go sail, whatever you wish to do. Worst case scenario you end up digging a hole in the ground to empty your bag. I swear i've had awkward situation (mostly awkward for me and myself), I have to do field trips and what not. So yeah, I've had to empty my bag in pretty curious conditions; the wood, sugar cane fields, beaches and others. You feel bad for 30 seconds but life must go on and if you don't force yourself into these things, you keep being scared of them so my tip is "Just do it".
I think the worst enemy of an ostomate is being sh*t-face/drunk... but even then, I've done great things in my drunkness (let's remember I got it at 14 so I had to live my experiences...) and managed not getting into too much ostomy related problem except once...
That being said... the only thing I am having a bit of issue convincing myself to do is things like climbing and parachute because i'm a bit scared of the harness but I know many have done it. But then again, the reason I don't face that fear is more of a financial reason than ostomy reason.
So yeah, if that surgery brings you into remission, I think you will be looking at the way more positive life than a loads of stoma-related anxieties!