Stimming

My son is 5 and a half months old and recently I've come to realize that something we thought was just quirky is actually called "stimming". If you don't know, this is self-stimulating behavior characterized by, among other things, wrist twirling. My son extends his arms out and will flex his wrists and rhythmically move his fingers. He seems to do it when he's trying to get our attention or wants something. Maybe when he's excited. I've read that this is often associated with autism. On the other hand, I've read that many neuro-typical babies do this and grow out of it. So far, my son seems to be hitting milestones- some even early. He smiles and giggles and makes eye contact. I want to hear from other mothers though. Do your babies stim? If you have older children, did they grow out of it? I appreciate any feedback. I'm having some anxiety about this. Either way, I intend to discuss with his pediatrician at our 6 month check up. Thanks!