It's hard for me to tell from that picture and her being a lucy, but she seems a little bit fat to me but not by much. I've had some with crazy growth rate, but doubling weight in 2 mos seems absolutely impossible. Maybe you wrote her weight down wrong when you got her or are basing it on the weight the seller said and they hadn't gotten a recent weight on her? That weight doesn't seem crazy for her age, just crazy if she was really half that 2 mos ago.