M.C.
It is normal behavior for them to do this. You need to be consistent in discipling her when she bites. A tap on the mouth, just hard enough to suprise her will wor. Make sure you tell and show her what mouths are for. Show her mouths are for giving kisses. Maybe let her bite and apple and say good girl. Mouths are for biting food, then show her a picture of a person and tell her we do not bite these just food. Have her give you kisses and let her see the good reaction verses biting and the bad reaction. Children are visual. They need to see what you mean. Good luck!