I can’t use my Face ID to download apps in the Apple Store even with it turned on

I have tried almost everything I can think of. My mom controls my Apple ID password because I am under age. To download apps I normally use my Face ID and then send a request but today it has prompted me to use my Apple ID password. I have checked to make sure that my Face ID is turned on for ITunes and Apple Store and it is. I have tried looking it up but it didn’t help give me any responses. I am afraid to turn it off and turn it back on again in case it signs me out and I have to enter the password again. Is there anything I can do?