At just 10 years old, Emily wears a size 12B bra, and carries around tampons in her back pack.
She’s not alone.
“The change in our diet and the change in our weight has had a massive impact on puberty,” she told This Glorious Mess hosts Holly Wainwright and Andrew Daddo.
Why are kids going through puberty as young as eight? Post continues…
“We have an obesity problem and we’re also taller – every generation is about three or four centimeters taller than the generation before it.
“Basically, we’re bigger people,” she said. “And we now know there’s link between the shape and size of our bodies and how early we go through puberty.”
By grade three most girls have started to develop breasts and by the time they reach grade six, at least 50 per cent of girls already have their period.
Dunn says we need to start the conversation about puberty earlier and talk to kids about how their body is going to change before it happens.
“There’s no point telling kids about puberty when they’ve already got their periods, are having wet dreams, or experiencing unwanted erections, and are completely baffled by it.
“We need to start having a conversation with kids about their bodies, about how their bodies are going to change, and take away some of that embarrassment at a younger age.”
Dunn believes schools should be responsible for teaching sexuality education at a younger age, but she says parents have a role to play too.
“Kids have more access to adult images and ideas than ever before,” she explained. “We need to provide counter-information to that because we don’t want kids picking up their sexual education from random sources online.”
Dunn recommends asking yourself some difficult questions as a parent, about how you relate to your own body, and how you talk about your own body with your kids. Then, she says, you should start an open dialogue with your kids.
"Let your child guide the conversation," she explains. "If you're open and honest with them from the time they're really young, and push through your own discomfort, it'll be normal to them and they'll ask their own questions.
"And as a parent, that's what you really want. You'd rather they came to you than went to their friend's sister or started googling it."
There's also plenty of great books that are written for children and explain exactly what's going to happen to their body during puberty.
Although Dunn says it's not necessary for women to talk to girls, and men to talk to boys about puberty, it's easier if you've been through it yourself.
"You remember yourself when you started to develop breasts and when you got your first period, so you can probably relate more personally."
Finally, Dunn recommends brushing up on your own puberty knowledge before bracing the subject with your kids.
"It's like when the kids in grade three bring home their long division and you have to remember how to do it," she said. "If you polish your own information before you talk, you'll feel more confident and you shouldn't get embarrassed."
Amanda Dunn's book, The New Puberty, is available now at all good bookshops.
Listen to the latest episode of This Glorious Mess.