kaitlyn to the dentist

I'm taking my oldest, who is only four years old, Kaitlyn to the dentist today. I wish I wish I wish that i was only taking her in because she was due for a cleaning. I think that they will clean her teeth, but i called and made the appointment because I'm worried she has a cavity. Actually I'm worried she has two cavities.
I am not sure how this could have happened. I am also not sure how she could have gone from great teeth to what looks like a cavity to me (I'm assuming it has to be really bad if it looks like a cavity to me) and i didn't notice till now.
I feel like a crappy mom.
I'll let you know how it goes.
One good thing, Kaitlyn is so happy to go to the dentist!! She thinks that little mirror they use to look at your teeth is the coolest thing ever. She has been bouncing off the walls to go since i told her i made the appointment last Friday.