A first for us

Today at the church nursery, Riley apparently jumped from being 17 months to 17 years old. We put her name tag on her back, she gave us kisses, and then proceeded to push open the door and walk into the room by herself! I know it was just the church nursery, but it felt like she was driving off to college.  What happened to separation anxiety and wanting to always be with us??? It was a sad moment, but also a happy one that she is adjusted to getting dropped off and wanting to play with other kids. I'm sure this is the first of many similar occasions, but I wanted to remember the first time...