Supplement her diet with food. High quality foods that contain protiens and calcium and d vitamins. It will require her having store bought milk fortified with vitamin d, let her go out in the sun which is a very good way to help her body to make vitamin d.
Being a vegitarian as an adult is fine but you are taking a serious risk of causeing even more harm to her by maintaining this vegan diet.
She is a baby and needs foods from every source available.