My DS is 3.4 and he has some repetitive behaviour. He flaps his hands when he's really excited and recently have been noticing him sort of pincering his fore and middle finger and thumb together, usually when he's describing something.
He also has repetitive behaviour with doors- though this has settled down a lot. When he was younger, when we took him places he would just shut and open doors and run through them, now he only opens and closes doors if he's feeling a bit anxious. He was also obsessed with 2 particular colours and numbers - this has also settled down but he still favours them. Again if he's feeling a bit anxious he tends to go for these things.
He's generally quite a busy child, always on the go. He can concentrate fine on most things, books etc. There were some concerns from our HV on his social development but he has come on quite well with this lately. There is lots of eye contact, joint attention, sharing experiences, imaginative play, no speech delay or any other delays. He's fully potty trained etc and sleeps well.
He's going to preschool in September so the picture will become clearer there. However, I know this behaviour is a major red flag. Could it be toddler obsessions or is it always autism? TIA.