It seems a little arbitrary to have her plateau at 12 when everyone else stops at 20.
hmm. Can you do anything about that in console on the PC? Like adjust her stats to match yours as you level up, f'rinstance?
I'm just starting with her, and I think my character adores her. When ask what her strengths are, and she says, "I really like punching things." I thought: really?
That doesn't sound all that great... but then she ran into the middle of 4 raiders with guns and just went bang, bang, bang, bang and walked back to me smiling while I was still screwing around reloading.
Actually, maybe she is a bit overpowered.