The day your child draws you a picture on her own, brings it to you, and you can clearly see what it is for the first time.
"Mom, I made you a jellyfish!"
Me: Do you want to try to write your name, Cass? Remeber, C for Cassidy? (draws C)
Cass: Ummmmmm, how about I draw an L? (writes the letter "L"). Wow.