Abby is starting to fight back

Two days ago I was blow drying my hair while Jack and Abby were watching Dora.  The next thing I knew, Jack came running into my room because Abby bit him.  He loves to bother her and until now she has just yelled. Well, I think she has realized that she can fight back. Later on that same day she knocked him over. Today she pushed him. Finally, she is old enough to fight back.