i agree, she will be fine. it is good for parents to get away.
we have a 4 year old and a 13 month old. i can count on my fingers how many times my 4 year old has spent the night away from home, and that is just at my moms house, which is less than a mile from our house. i didn't leave him overnight until he was like 2.5, but now with number 2 i realize they will be fine, and enjoy being away as much as we do. i have only left 13 month old once over night and worried the whole time. but when i got home, he didn't even want to come to me. it made me sad, but at least i knew he was having a great time. in september, dh and i are going to a wedding in another state and will be leaving them for 2 nights. i am looking so foward to it. it will be the longest the two of us have spent alone since becomming mommy and daddy. go enjoy yourself and don't worry what others may think, as long as you and you daughter a comfortable, then that is all that matters.