IMHO
Your baby is going to get alot of attention at the party regardless because she is a baby. If you want to wear that dress on her I say go for it
Is it a comfortable dress?. Some dresses are so beautiful but aren't comfortable. I have a daughter finally after 3 boys and I have always dressed her how I wanted to for any party or occasion I figured I deserve to show her off. I waited so long to be able to buy dresses. My dh loves it too. I have had comments about how she is dressed A women I didn't even know at a graduation party recently said how beautiful she looked she had a daughter too the same age as mine and she was dressed in jean shorts and a top. When she saw that I also had 3 boys she told me that explains why my daughter was dressed the way she was( in a sundress with matching bowband socks and shoes.)
If the parents dress down there daughter. Then regardless of what you put on her she will still be beautifully dressed. I went to a realtives first birthday party for their daughter and she wore jeans and a birthday girl t-shirt.I didn't have my baby daughter at the time but if I did She would have been dressed in a beautiful dress, Life is too short to care what others think especially about somthing so trivial as a dress on a baby.
I just feel as mothers of an only girl after all our bundles of blue We deserve to dress our only daughter how we see fit. They will be older soon enough and tell us what they will be wearing. I myself am not looking forward to that day
Please post a pic of your daughter in whatever dress she does wear