I signed up my youngest for kindergarten a couple of weeks ago, and I realized the baby years were officially behind us. Since then, a bunch of other things have really driven home the point that, yup, my sons -- now 4 and 5 -- are in the “big boy” category.

Here are five signs that my kids are no longer babies:

1. My oldest, Kai, made the announcement that he “no longer likes trains with faces.” Real locomotive footage is apparently fine, but Thomas and Percy can hit the road.

2. I finally threw away an entire grocery bag full of teeny, tiny, stripy socks. (That was kinda sad.)

3. Kai told me the difference between boys and girls are that girls’ penises are hiding.

4. Levi realized his name is on the booty of blue jeans. (He's filled with glee every time he sees a little red tag. And when he saw an entire display at Kohl's Department Store, complete with large "Levi's" signage, he was absolutely overjoyed. There was hand clapping and everything.)

5. Levi said he wanted to eat more “healthy food.” Unfortunately, he insists on dipping all of his healthy food -- raw broccoli, carrots, apples -- in ketchup. He might be a "big boy," but his taste buds still have a way to go in the maturity category.