I was a unit manager (GM) for The Waffle House for about ten years. Apparently some lady wrote a scathing letter to corporate because "that poor girl should be in school!". I was twenty seven.
It gets MUCH less irritating as you age. Last summer, at 32 I was asked for my student ID at the ticket booth for a high school football game my daughter was cheering at.
Count your blessings. I saw my former babysitter's daughter the other day. I remember her as a fresh faced, beautiful 18 year old. She is now 25 with three deep wrinkles under each eye and a host of others. My daughter was shocked. As soon as we walked away she grabbed my arm and said, "Tiffany looks so old Mom!!!"
It doesn't bother me at all anymore. Quite flattering, actually.