Apparently anxiety about clothing is reasonably common. My DS has been wearing the same 3 pairs of pants for the last year and not much better for tops. He only wants to wear the clothes he is ''used to''. He is worried about what people would say if he wears something different. We have had a lady in who took some photos of him with his old and new clothes and she is going to make a social story for him about wearing the new ones. I wouldn't push it except that he starts school in 3 months and has to wear a uniform. I have tried the logic thing many times but it hasn't worked for us.

Your DS does sound very sensitive though. My suggestion would be to get him the blue shirt, perhaps at this stage he just needs to fit in. He is only little, still plenty of time to find that inner beat to march to.