Growing like a weed!

We measured Liddy tonight and she grew an inch since August. This girl is growing like a weed. She is already outgrowing her size 5 and now wearing 6's!! A year ago she was just starting size 4. How does this happen? And for the record she is 3'7 1/2" which is 90%. I should start taking her picture in front of the same background so we can watch her grow.