What do i wear..?

im 18. 5,4 & around 100 or so pounds. im going to a wedding in 3 days and I have absolutely nothing to wear, so ill be getting an outfit. what style should I shoot for (ill upload a body pic to show what my body looks like.) my boyfriend said hes probably going to be wearing a black or grey suit. I plan on straightening my hair and wearing it down. my hair length is atleast a little bit longer than the middle of my back.

Also I don't know what shoes to wear either. I was born with a small bump on the side of my feet that most people would think is a bone sticking out, but its not. My toe nails aren't done either since I don't get them done anymore so I don't really want to show my feet. any ideas? please don't just read this and not comment. I need advice.😧