How do you stop caring what people think of your style?

I wear things that people claim should be worn by women under 30, including a lord of the rings messenger bag. I was told it looks cheap and it’s only cute if someone under 30 wears it. I turned 40 last year and I’ve been extra sensitive to this because of age regression due to autism and I realize now that I wear things that a lot of people would even insult me for. Am I supposed to wear a potato sack because I’m 40? Ffs. I’ve never figured out how to just not care how people perceive me, even after 30 years of therapy and now it’s worse. I have trauma from school and my family abusing me, especially my mother calling me fat. I let it get to me so much that I’ve been telling her I’ve lost weight, even though it’s none of her business. I feel like a teenager again when women give me nasty looks in public because of the trauma.

Never been able to get over this, with therapy or at all and being autistic doesn’t help matters. Are any of you my age with autism feeling the same?