Is this dress acceptable for a wedding?

My fiance is a groomsman in his brothers wedding. Is this an acceptable dress? I'll have my hair and makeup done and wear heals, it was 6.99 at Ross it was cheap! I don’t want to look cheap though lol

I'm pregnant and finding anything that looks nice is hard these days lol

It's a semi formal or dressy casual wedding, but it’s outdoors and summery. he's wearing a black suit and bow tie, I like the black one but I also have the bottom picture if the black dress is a no go. Pls help lol