I was mistaken for a woman nearly a decade younger than I. I am in my late 30s and my husband is in his mid 40s. We had to attend a family function and one of my brothers-in-law's relatives was there. My brother and I had only met this relative once before at a wedding and that was nearly 10 years ago. My brother and his wife are almost a decade younger than I am approximately 15 years younger than my husband. Usually I don't think about how old or not I look so I was surprised when the BIL's relative walked up to my husband said "oh you must be [name of younger brother] and you must be [name of younger brother's wife]."  My husband laughed and said no and introduced himself. The relative turned and looked at me confused and said "Well then which one of you is the oldest [of the siblings]? I must have gotten confused."  I said that no that was correct, I am the oldest. The fat relative asked me my age and I promptly said my age.  I was then told that I was lying and that I looked too young and there was no way I was my age. I said, well, I dye my hair, it's almost really all gray and then I offered to get out my driver's license. [BTW I dye my hair a normal freaking color, not blue or something stupid]. The fat relative asked me what kind of makeup I wear, what my skin care routine is and was shocked when I called out everyday, you can find in any store brand names. Fat relative then demanded to know what my secret was. I just shrugged my shoulders because it was a family gathering and I couldn't very well blurt out, "well, I drink water, water, water, and more water. Oh yeah, I don't eat crap and I try to get in as much exercise as I can when I'm not hurting.".  Seriously I don't think that I look that young. I think I look about average for my age. It isn't my fault they eat and drink so much crap and prematurely age so badly. I'm still not sure whether to feel flattered or put on the spot but I'm leaning towards the latter.