When The Boy was on treatment, he grew very slowly. It seemed like he wore 18 month clothes forever!
When he was about 4 months, I thought he was big because he was starting to wear 9 month clothing. Well, Ender is nearly 4 months and is starting to OUTGROW 9 month clothing.
I am still thankful every time I need to switch out their clothing for the next size up, because it means they are growing.