I have always looked a lot younger, although at 52 I would say things are starting to catch up. But at 20, I still looked like a teenager; at 30 I still looked 18; at 40 I was told a lot that people thought I was in my twenties. I actually still got carded at 40, when buying wine in the supermarket or when entering a nightclub or bar. At 27 I had my beer grabbed and taken away angrily from me by a bartender passing through the club who didn't know I'd bought it from the other bartender at the bar perfectly legally.
When I was about 40, I actually dated a 26 year old guy for a while. One night we entered a bar with carding on the door. The door guy didn't look at us funny at all, took my boyfriend's ID, checked it out, handed it back. Took my ID in his hand...and suddenly looked up at me and said "OHHHH......uh, okayyyyy!! !" with a huge grin on his face, realizing that I was a MUCH older woman on a date with this very young man!
I still get someone I newly encounter expressing shock when I tell them my age, so I guess it's still there, but the "gap" is shortening, in that instead of thinking I'm 20 years younger people peg me more for maybe ten or fifteen years younger now. The gap of mistaken age is closing inward now and although I take care of myself, I'm sure one day it will no longer be there, but that's natural.
I also am short and have a high, mild, girlish pitch of voice - I sound like a child on the phone, and have been asked by, for example, my bank calling, if my mother is available!! So this all adds to the impression as well.
I'll tell you though, when I was 30 and still taken for a kid, it bugged the HELL out of me! Because I was desperate to be taken for a grownup, yet people were assuming they were dealing with a much younger person, and yes, there can be condescension when that happens. I got treated as young and it felt like an affront.
Now that I am older, I'm not so mad about it anymore, hahahah! Go ahead, treat me like I'm only 35! I'm delighted to get that compliment!
I would say to you, try not to get too upset, because time will cure this misunderstanding. I was just like you, really fed up with always being taken for younger, because it's true it IS insulting at that stage of life, because people DO treat you with unwarranted condescension when they truly believe it's a much younger person they're dealing with. I totally got that.
But remember you will age and this problem will fade, even if they still think you're ten years behind where you really are -- once that ten years behind is still up in the adult range, the mistake won't be so painful to be subjected to.
.