When you’re NT you passively absorb more about aesthetics from your peers as you grow up. Signifiers of age and your social groups are something you practice and get good at, whether or not anyone tells you to.

So autistics have to specifically be very interested in aesthetics to pick up on it. Or be pushed to socially. There’s plenty of us who don’t look like adults in children’s clothes (not me), you just don’t notice them.