Autism?

My two year old son is a late talker. He is just starting to say a bunch of words now and actually associating them with an object. Like cookie, he knows what a cookie is, bubbles, ball, and so on. He’s got a ton of words under his belt now. But it wasn’t until he turn 2 that he started taking off. He didn’t point for a while or show much interest in other kids, but is starting to now. He points and he likes to play with kids... he’s doing pretty much everything good at this point, however he flaps his arms when he is excited and now I noticed he just started waving his arms up by his ears when he’s frustrated or mad... is this a sign of autism? Has anyone else had kids do this and end up not being diagnosed with autism? I feel silly worrying about it since it’s the only thing that he does now that kind of concerns me...because he is improving like I said above. Anyone have an experience with this? Thanks!