How old is too old for someone to be a flowergirl?

In my wedding party I have 4 bridesmaids, and then I was going to have 2 junior bridesmaids. One of the junior bridesmaids is 11 and will be 12 by the time my wedding comes around. The other one is 6 and will be 7 before the wedding. I thought 7 might have been too old to be a flowergirl, but the other day she asked me, "does this mean I get to throw flowers down??". Now I am kind of reconsidering having her be a flowergirl in the wedding, do you think shes too old for it? Do I also need a ring barrer?