You don't want this to turn into a major battle with your DD or indeed your DMother. It's not a massive deal but you don't feel uncomfortable, and you are the parent.
If it were dressed down with Doc Martin Boots, opaque tights and grandad cardi in a grungier style then it would just be short. If it is accessorised with heels and bling jewellery it would be over the top for a 12 yrs old, and more suitable for older teenagers in a club. You can't force which way your daughter chooses to wear it. I have a 12yr old DD and they have clear ideas of what is suitable clothing.
The real issue isn't the dress. It is your mother choosing the outfit and giving it your daughter. Thank your mother graciously (to prevent this being an issue) but explain as your DD prefers to chose her own clothes and is very picky, that in future a voucher would be more appropriate. And repeat. And repeat. And repeat. And repeat. Until DM gets the message
Your options:
- Try to get a refund if possible
- If not go down grungier route, leggings/ boyfriend cardi, boots
- If you have the funds to replace in terms of ££deliberately ignore washing instructions, there may be an unfortunate laundry accident, the dress gets ruined and give your daughter some spending money to buy a more suitable alternative.
Keep an eye on granny, she may be surreptitiously trying to undermine your authority, as she may not approve of your lifestyle choices and wants to interfere.
Forwarned is forearmed and all that. HTH