The facts about puberty (for girls)

You look in a mirror one morning and notice you're taller -- and rounder. Through your dressing gown, you see your breasts are bigger. You don't remember looking like that a few weeks ago! Over the next few weeks, you start noticing hair in places you've never had hair before. You've heard girls at school talk about getting their periods, and you wonder if that will happen to you soon. You feel ultra-confident, and then super-sensitive -- all in the same day. What in the world is going on? Welcome to puberty.

Technically speaking, puberty is nature's way of transforming a child into an adult, all for the sake of reproduction. While both girls and boys go through puberty, girls reach puberty and sexual maturity at earlier ages than boys do.

So what's causing all of these changes? Hormones! Actually, the female hormone oestrogen is the main one that's triggering all the changes in your body. Let's look at some of the changes girls can expect at puberty.

Increase in height and weight

Starting at around age nine, girls begin to gain about 17% to 18% of their adult height. If someone has commented that you are "all hands and feet," it's true! Your limbs grow first, then your trunk. Most girls reach their peak height growth about six months before they start their first period.

You'll probably gain weight in puberty - most girls do. You may notice more body fat along the upper arms, thighs, and upper back. Your hips will grow rounder and wider; your waist will become narrower.

If you are gaining weight too fast, you may need to increase your exercise and substitute fruit and vegetables for junk foods.

Puberty breast development

Breast development is an early sign of puberty in girls. This can happen before the age of nine in some girls, but later in others.

If you are self-conscious, you might want to start wearing a "training bra," which is a soft bra with no real support.

Talk to your mum, older sister, or an aunt about buying a training bra. They can take your bust measurement to make sure you have one that is comfortable and lets you feel confident in your clothes.

Increase in hair

While for most girls, breast development is the first sign of puberty, others might first notice pubic hair. An increase in hair on your arms and legs, in your armpits, and around your pubic area happens to girls early in puberty.

If you want to shave your legs and underarms, ask your mum or another woman you trust about selecting the safest razor. Someone who is experienced in shaving needs to show you how to shave safely, using a gentle shaving cream, water, and a razor. Or ask them about an epilator, a device which very quickly pulls out unwanted hair.