I agree with the others, that you have a beautiful complexion but the makeup just makes you look more polished.
I think that part of your reaction has to do with simply not being used to seeing yourself like that. I am going through something similar—I am starting to wear makeup after not having worn it for years. Today, I just wore mascara and blush and a very light lip color. When I looked in the mirror, I was quite startled! It looks so different. But others won't have the same strong reaction. They'll just think, "She looks pretty."
I got a makeup consultation before I bought the makeup I'm wearing now (I'm terrible with picking colors myself), and when I came home and really got a good look at myself in the mirror, I was stunned. I said to myself, "I will never have to worry about having a good hair day again, because with properly applied makeup, my face is so eye-catching as to make my hair almost unimportant!" And it's true. Well-applied makeup adds that polished look that Angie is always talking about. I am starting to see that if a person takes care to be polished—some well-chosen, well-applied makeup, nicely groomed nails, nice hair (doesn't have to be perfect, though)—she looks fabulous even if her outfit is only so-so. I am starting to feel like makeup is one very helpful part of an overall fab look. It's kind of like an accessory.