Jenni, are you physically similar to other women you are related to? If not, it might be a good idea to get checked like Raindrop said above. As for you face looking young...one of these days you will absolutely LOVE it! I was carded for alcohol until I was in my mid 30s.
When I was 29 I got a job at a place which was mostly teenagers working, and they thought I was one of them. It's not a curse, tho it may seem like it now. As someone above said, you might want to dress more professionally, and maybe an older hairstyle?