We seem to have this whacky idea that your body pretty much stays the same until these kinds of things come along - which is a very silly way of thinking, indeed.
Because you don't just slip into your 'adult body' when you're 18 and then stay in that same body for the next 20 years or so. We're not Sims.
In fact, the most significant changes to your body actually take place when you're in your 20s.
Yes, your little old 20s!
Watch: Here's what you can do to help improve your daughter's body image. Post continues below.
While your 20s is a time when you'll experience a whirlwind of highs and lows (new careers! romantic relationships! breakups! mi goreng!), it's also an active time for biological shifts - like, everything from your brain to vagina is up for development.
It's just that no one really talks about it. Especially when it comes to women's bodies. (Classic).
But, that's why we're here. We've talked to some experts to find out some of the completely normal things that can happen to a women's body in her 20s, and exactly what to expect.
Your body changes shape.
Despite what society and social media might make you believe, your body shape changing as you mature into womanhood is a very normal thing that will happen.
Very. Bloody. Normal.
"Bone and muscle development and growth peak while we’re in our 20s, but as hormone levels naturally and normally shift so too can body shape and where we store our fat," explains medical doctor and psychiatry resident Dr Kieran Kennedy.