Child account though im almost 19

You would be better to make another account as you cannot change your age again.

If you know what the parental account was that setup your account you can sign in at account.microsoft.com/family with it and remove yourself from the family.

If you do this and try and sign in and it says that you need a parent account that means the DOB when the account was originally setup has still not reached its 18th birthday and would by law need an adult account attached to it till it reaches its 18th
birthday that was put in when the account was originally setup.

If you have changed the DOB on your account from what it was originally there is no way to tell what it was when it was originally setup.

If you do not know the adult account that was attached to your account you can try and sign in with your account at account.microsoft.com/family and see if it will show you there what your parental account is.

where would i check that date?

The birth date on and Xbox live cannot be changed. If you originally had a different date listed on your MS account and then changed it on account.microsoft.com that will not change it on your XBL account.

Yeah, it's still a child account. There is a parental account attached to it. Almost everything I was able to move over to my current account, so I control almost everything. But there are still disadvantages to having a child account, of course. But yes,
it's still a child account.