Okay, so I've had my current gamertag a while and wanting a change. But before I do, I was wanting to make sure that if I change my gamertag I'll still be able to load my existing worlds. I've tried searching, but can't find a post I thought I read once that said it would prevent you from loading your saves if you change your gamertag.
Yes, you will be able to load your worlds just fine. Your gamesaves are binded to your account through your 'profile ID', which isn't altered by changing the name of it.
Gamertag Change