I have a 16 month old and she has been taking her diaper off when its messy. She also seems to know when she has to go.
What's the typical age that kids get potty trained?
That is a typical age. They will let you know when they are ready.
Now I would make sure you help her know that going on the potty is a very good thing!
The Mayo Clinic has a good set of questions you should ask yourself before starting:
Don't get discouraged if she loses interest in potty training. It happened with my son.