What is the average shoe size for a 12 year old 5'1 girl?

I'm 13 now but when I was 12 i was 5'0" tall and fit in a 10/10 and a half. I think there is no certain size of shoe a 12 year old girls should be.You either have big feet or small feet. Also if you have big feet it doesn't mean you'll be tall.My sisters friend who is 18 years old is a 10 and is only 5'5".