I still haven’t started it but I’m ten

It's totally normal to not have your period yet when you're ten. Most girls get their first period between ages 10 and 15, so you're right in the middle of that window.

Everyone's body is different, so there's no exact age when it has to happen. You might start noticing other signs of puberty first, like your breasts developing or some white or yellowish discharge in your underwear. Those are usually clues that your period will be here in a few months or a year or two.

Btw if you want to find out roughly when yours is coming, there's a quiz on this site: how close is my first period? — it literally takes like a minute.