ANDY'S ANSWER: On average, girls grow until they are 14 or 15 years old and boys can stil be growing into their early 20's!  You may never be really tall, but that doesn't mean you aren't normal. Someone has to be the shortest in the class just as someone has to be the tallest. Regardless you could still have a growing spurt which may put you ahead of someone else. The shortest boy in my grade 7 class was the tallest boy in my grade 10 class. it's just too early to know for sure how tall you will be by the time you're full grown.