Women or girls help! I am to young?

I just turned 11 on the 27 of last month and 2 days after i got my period i think i am to young and when i told my mom she said she got hers in 6th grade i am in 5th tho! And none of my friends have theres yet soi i am very scard what should i do? Abd i cant tell my teacher he us a guy and kinda creepy