Should I feel Guilty?

Last week was Carson's first day of preschool.  He was so excited to go and I was excited for him to go. Well the first day came and he put on his back pack and said "k mom its time". We got there and he ran in and started playing with the kids. He didn't even care that I was there. I finally went over to him and said "ok honey I am leaving" and tried to hug him. He looked at me and and said "ok bye!". No hug he was to busy playing with the kids. I left and I thought hmmm my baby is growing up and obviously doesn't need me as much anymore. Should I cry? Should I be upset? What am I going to do with him gone for a couple hours? PARTY!!!! I think I was just as excited as he was for him to start going to school. He absolutely loves going so it makes me happy to send him. So the question is should I feel guilty for not crying? Or even for not feeling sad?