Oh dear lol, Eau de Mothball perfume on the Brides wedding day, probably won’t be welcome!
If the dress is synthetic material, it’s unlikely to attract Moth damage as they much prefare natural fibres to feed on. I still have my Ronald Joyce wedding dress from 34 years ago hanging in my walk in wardrobe, just covered by its original dust bag and it’s fine. It’s cream polyester satin and lace, it no longer fits me, but l keep it for sentimental reasons. One of my Daughters has hinted that she would like to borrow it for her second marriage in a couple of years time.
I would not worry about storing your daughters dress for a few months more than planned, the chances are that it’s been in its original wrapper for over a year already, awaiting being sold.
A few more extra months will not make a difference, just keep it in a cool dry place, and away from any direct sunlight that may fade it.