My little Jenny is starting to bite

[Marnie]

She's 2 1/2 months old and very friendly and wants alot of attention. She just constantly wants me to pet her, if I don't and turn my back, she'll bite me. The other day, my friend was here looking at her and she just pushed her back and each time Sweat Pea would come after her than with her ears laid back and I think was really going to bite her again, each time she just pushed her back, she got angrier and came at her a little more nastier, she looked serious too. I know I can't be hitting her on the nose and if I can't push her back, how do I keep her from biting us?