Do I really look that young?

So yesterday I was at this picnic that Jonas's school was throwing. A couple hours into the picnic the parents got out the glühwein and one of the women started to pass it around to the various people around the fire. She walks up to me and says, "Would you like some, wait, never mind you're too young." and walks away before I could even react. Now if this had taken place in the US it wouldn't of really made much of a difference to me since I only just turned 21 at the end of May. But this is Germany! The drinking age in Germany is 16! That woman had just accused me of being 15! Let's do some basic math here, 21 minus 15 equals 6. That woman thought I was 6 years younger than I am, at the least! I didn't even want to ask her how old she thought I was cause I was afraid of the answer I'd get. :( She thought I was 15... I went up to her afterwards cause I wanted some glühwein and I told her I was 21 and she said sorry but I should take it as a compliment cause that just means that in 10 years when I'm 31 people will think I'm 25 but still, once I get back to the states I'm gonna get carded till I"m 30 at places that never card anyone else! I'm sure I'll start to appreciate it as time goes by but right now I just want to go pout in a corner. Wah! And I bet I'll look even younger then! I can't win!