Screentime limits still in place after turning 18

I recently turned 18, and with that, received full control of my Apple account from my parents. I had previously had a daily limit, which was meant to go away once I turned 18. My parents can no longer control my screen. time, and cannot get rid of it themselves, but this limit still annoyingly remains, and I cannot change it myself. I am still within a family, to use the Apple Music subscription, though I don't think that should change anything. It requires a "screen time passcode" of four numbers to change, which neither of us know.

How can I control my screen time, as I should be meant to? The methods I previously had to circumvent the controls no longer work as well, and I'd really like to know how I could fully take control of my account. What do I need to do to do that?