Is 11 too old to be a flower girl?

Hey there! I'm somewhat recently engaged (last October) and am getting married soonish (next October). I had a quick question about my fiance's sister. She's going to be 11 when we have the ceremony and of course we want her to be a big part of our special day since she's the only sister we have between us. I've had the thought that most flower girls seem to be in the 3-5 range so she might feel like she's being given a "baby job." On the other hand, our wedding party is pretty small and I only have a bridesmaid and a maid of honor, who are both my friends from high school so I don't know if she would feel weird being around older women. Any thoughts? We're definitely going to talk to her about it to see how she feels, but is there a way to make her feel more included as a flower girl or a bridesmaid?

Edit: omg thanks so much for all the responses. I'm definitely going to ask her if she'd prefer flower girl or Jr bridesmaid or possibly a bit of both jobs