I'm not yet of legal age and have created an xboxlive profile and would now like to reduce my real age, but I don't know whether this will cause me to lose my gamepass ultimate live gold or it play subscription and of course my games.
You don't create a new account, you still have an old one, if it were so there would be a warning.
100% I'm not sure but 99.9%
OK thank you
If you set up your account with a minor, some games may no longer be displayed correctly in the shop, for example. But the games you bought stay because those are yours. Can't nobody do anything
If you signed up for Xbox LIVE with a different account, you can't change your age. If you are under 18 on your current account, you will need to set up a new Xbox LIVE account with a different date of birth if you wish to play M-rated games or download certain movies and media.