My sister got her period at 10 1/2 and I'm 12 and didn't get it yet

It's totally normal that your sister got her period earlier than you, and it doesn't mean anything is off. Everyone's body has its own schedule for puberty, so there's a pretty wide range for when your period can decide to show up.

Most girls get their first period between 10 and 15 years old. Your sister was on the earlier side, and you're still well within what's considered normal. Usually, you go through a bunch of other changes before your period starts anyway. Like, typically, breasts start developing first, then you get some vaginal discharge after that. And a big growth spurt usually happens a while before your period, too, so your body just keeps changing like crazy.

Keep an eye out for those other body changes because they're usually little hints that your period is getting closer. But really, don't sweat it! It'll happen when it happens. If you're super curious about roughly when yours might arrive, there's a fun quiz on this site that helps you figure it out: how close is my first period?