Look, almost any smart/formal/party-type dress for a little girl will be sold online with additonal 'bridesmaid' and 'flowergirl' keywords, simply to boost the rankings (and, of course, to help out those who are looking for such a thing.) Sellers often add 'princess' to the listing for the same reason, but it doesn't mean people will think a kid wearning such a dress is actually royal.
I can see that PP are sensitive to it because they have direct experience of pushy cunts doing this type of thing deliberately to upset or manipulate the bride, but that doesn't make the OP such a person. She just wants to keep her DDhappy nd get her money's worth out of the DD's party frock.