>>31685
https://en.wikipedia.org/wiki/Puberty
"On average, females begin puberty at ages 10–11 and complete puberty at ages 15–17"

So she might have not just began sexually maturing, but possibly already ended it at that stage. Age of consent in most countries in the world is 14-16, and so was/is in most USA states, probably including hers.
https://en.wikipedia.org/wiki/Ages_of_consent_in_the_United_States