What does your husband think? Can you afford the dress? You might think it's ugly, but it's not your wedding.
If you and your husband agree you can not afford the dress, let the bride know.....she may be willing to foot the bill or part of it and remember there will be shoes possibly tights needed as well.
Yes it would be rude of you to ask if YOU can pick out a different dress.
"an ugly one at that.....she won't be able to wear it again".....I sense a little anamosity going on here. Of course you child could wear that dress again, unless you wait until she grows out of it. She's 3, it could be altered if it's a long dress or you could put it in a resale shop or donate it. Doesn't sound like your too happy about this wedding. Have you served as a bridesmaid/matron in any weddings that your husband hasn't been a groomsman? Did you and he have the wedding of your dreams?
If your husband is looking forward to this and wants to show off your daughter, don't rain on their parade.
Blessings....