So I will be making the dresses for my flower girl and bridesmaids for my wedding and the flower girl is a chunky little 6 year old, but she will be 7 when I get married, a year from now, however, I found the PERFECT fabric on sale and I was wondering how many yards you thought I would need to make a dress similar to this

Just with less ruffles (maybe further down, idk those ruffles just seem too high...) Maybe no ruffles at all, I'm new to clothing (been sewing since I was 8 but haven't sewed clothes before!

Anyways I'm starting to think that a dress with the same type of top but goes straight down then use the fabric from my bridesmaid dresses to make the little tie...
Any ideas would be great! Thanks for any and all help!!

I am thinking I'll probably get three yards to be on the safe side, I know I only need four yards for my bridesmaids, so I think three should be plenty. Do you agree?