Invited to a VERY extravagant fancy 21st birthday party (I am early twenties as well), but I have literally nothing to wear. The dress code is "smart casual" but it's an evening event and I assume this means more than the standard "no rips, no trainers" way I usually interpret it 
I never wear dresses or skirts, and I have a very very small wardrobe. In terms of smart stuff I have one "black tie" outfit which is a black tuxedo with a black silk shirt (a la emma watson) but I think this is too "black" for a colourful birthday party, and probably too formal as well. I also have a suit I wear for interviews and the like (obviously not appropriate here) and...that's it. The rest of my clothes is jeans and t-shirts for casual, and shirts and chinos for work (pretty casual workplace)
I need one "party" outfit that I can wear to this event and events of a similar type. (I embrace the minimalist wardrobe and the idea of "one" winter coat, "one" party outfit, "one" swimsuit etc). I currently own a very lovely pair of navy suede flat shoes/booties that I currently wear only about once a year because they don't go with anything else, so if you could suggest an outfit that would go with those shoes (so I don't have to buy yet another pair- excessive shoes are my minimalist undoing!) that would be a bonus!
I want to look good, but I also want to look like myself, which is quite a "tomboyish" style to be honest, I've never worn heels in my entire life. I would consider a dress, if it was the "right" type (but I can't describe what that type would be, apart from not body clinging!) or a trousers outfit. If all else fails, I will wear my navy shoes with my navy chinos and a crisp white fitted shirt, and buy some jewelry to accessorize (I own a chunky silver bracelet someone gave me for my 18th, but that's it)
Thank you mumsnet fairies!