Age things

I got an email from meta saying that a child under the age of 13 is using my headset (i made another account for my little sister) and that it will suspend my account on June 21 2026 if I don’t confirm my age. However, I am older than 13 (my sister isnt and we used her number to sign it up) and I tried to confirm my age but the link just puts me on a page to sign in and when I do it doesn't let me do anything but change my language? How do I confirm my age?