Not really. Bounties are a basis of how dangerous they are to the government not necessarily battle power. Robin in particular has always had a high bounty even as a child.
I don't think she could take zoro even post time skip. Her ability is very weak against slashing weapons, as shown on dressrosa. Without haki, any competent swordsman is going to give her trouble. Though with haki her ability is OP so I have no idea where oda goes with her as far as power progression.