On a slightly more serious note, I would suggest a dress. As it's close to a "summer" wedding, you can definitely opt for something bright and colourful, possibly somewhat short if that's your jam. Absolutely no wearing of the colour white or black unless it's just a splash. You don't want to upstage the bride with white and it's not a funeral or a dinner party so don't go with black.
I would also say this is your one opportunity - outside of Ladies Day at the races to wear an absolutely outrageous hat. I personally feel it's a small fashion crime - or at least a minor sin of opportunity to not wear a hat to a wedding. Unlike men, you don't have to remove them in Church either, if the wedding is inside a church.
My experience of weddings is that it's only really the men that change, possibly from a (morning) suit at the wedding to a tuxedo for am evening dinner reception. It's just that tuxedos are evening wear and morning suits are the formal daytime apparel for men. But this is by no means expected.
SS