Help! Need dress for wedding evening do

[DressMe]

Name changed just in case.

I'm early 30's, three children, youngest of which is 3 months old. I'm going to a wedding reception and need a dress. Fashion is not my strongest point and I have no idea what suits me.

I'm 5ft, size 14-16 and have no idea how to make this look ok! I usually dress very casually. I avoid formal events as I have no idea what to wear!

Any suggestions of styles of dresses that will suit my short, round shape??