Hello K.,
How are you doing? I can relate to your situation, my youngest daughter who is now 4 had this same type of behavior issues when she was younger, about 2 years old. While she was in a daycare facility with the younger infants, most of which were just learning to walk a few steps. She seemed older for her age and had learned from her bigger sister how to stand, walk and run at an earlier age than my first. Anyways, she played rougher with these infants usually causing them to fall down by continually bumping into them, then she too started to bite, mostly out of frustration. Because when they decided to place her (even though she was smaller) in a class with toddlers, she stopped the biting. They reason I believe my daughter was acting out in frustration was because certain behaviors over the years keep showing there mean little heads. Lets just put it this way, the ladies that I use to work with got a good laugh when on a daily basis I would have to list all the things my lil' one should not do to others because she would not want these things done to her.
That is silly that they would suggest for you to take her to a Behavioral specialist, sounds to me like they are overreacting.