I've been watching from the shadows, mostly, because I, like many others, am bad at saying things. But this is SO good for you! Good health is priceless... I mean, aside from the horrible medical bills. Maybe that came out wrong.
SEE WHY I DON'T DO THIS NORMALLY?!
You're also lucky because you're getting this done young. It'll probably be a lot easier for your body to adapt. Good luck, and a swift recovery after your surgery!