How to change Meta Quest Account age

A few months ago my little brother (13) got a Quest 3 for his birthday and only used it 3 times since he got it so he said I could have it. I am an adult and when I tried to get games I would like to play I couldn't download them due to the content maturity rating being to high (the games being M rated). I haven't had much luck looking it up but is there any way to update the accounts age or no. When he got the headset my brother bought a couple games with money like Beat Saber and stuff so I don't want to just make a new account and have to buy them again. Thanks