Need reassurance...

Hey guys I am posting anon I think other person is on this app..

Anyway...

My sis in law and I had our babies a week apart.. they are 4 mo old and we are always talking about what our babies are doing.

I've been trying to get baby to laugh forever and this morning I get a video of her kid full on stomach laugh. I know I know don't compare all babies develop at their own rate but I can't help it. I feel horrible that I'm questioning milestones at all but I'm bummed. I feel like it's never gonna happen!

Just venting..