Well, girls get a head start on puberty — and growing taller — because they usually start these changes between the ages of 8 and 13. Most boys, on the other hand, don't begin until between the ages of 9 and 14. So that's why girls are often taller than boys during that time.

Most boys may catch up — and even grow taller than girls. But it's also important to remember that your genetics play a role in height. So if your mom and dad are tall, you're more likely to be tall. And if your mom and dad are kind of short, you may be short, too. But nothing is definite.

Remember that puberty happens on its own schedule, so there's no rushing it if you're a little slower to develop muscles. Maybe you've considered lifting weights to help yourself get bigger. It's important to know that if you haven't quite reached puberty, this will tone your muscles, but it won't build up any muscles yet.

Eating nutritious food and being active (like riding your bike, swimming, and playing sports) will help you be a kid who's strong and fit. In time, you'll reach puberty and you can start building your muscles, too.

If you decide to try lifting weights, first let your doctor know you are interested. He or she may tell you to hold off on weightlifting for a bit or give you some advice on how to start. If your doctor discourages weightlifting, try some other ways to work out. Resistance bands, which are like big rubber bands, are a great way to help build your strength without putting too much strain on your muscles.

Remember that puberty happens on its own schedule, so there's no rushing it if you're a little slower to develop muscles. Maybe you've considered lifting weights to help yourself get bigger. It's important to know that if you haven't quite reached puberty, this will tone your muscles, but it won't build up any muscles yet.

Eating nutritious food and being active (like riding your bike, swimming, and playing sports) will help you be a kid who's strong and fit. In time, you'll reach puberty and you can start building your muscles, too.

If you decide to try lifting weights, first let your doctor know you are interested. He or she may tell you to hold off on weightlifting for a bit or give you some advice on how to start. If your doctor discourages weightlifting, try some other ways to work out. Resistance bands, which are like big rubber bands, are a great way to help build your strength without putting too much strain on your muscles.