Maid of honor dress ok or not?

The bride was very generous in allowing you to select your own dress. I would, however, run it by her first. Yes, it is a lovely dress, but it appears to have a train and unless that is acceptable and she does not think it will fit in with the other brides maids dresses, then the train could pose a problem. In which case, it could be hemmed to a floor length gown.