Should I be worried?

Before I start my son is 6, he’ll be 7 at the end of March. My son had a dentist appointment almost 6 months ago and due for his next appointment next month. My husband and I will be asking this at his appointment but I want to know other parents experiences. Anyways my husband and I noticed that he hasn’t had a wiggly tooth or a tooth that’s fallen out. We’re kind of getting worried only because when we go to his school for lunch or volunteer work we notice that the kids in his class or grade level are missing teeth or you can tell they have some adult teeth. I know every kid is different but my husband and I thought he should have at least on tooth missing by now.