What to wear, what to wear?

i live in florida...so the weather is pretty bipolar. It's usually a little chilly at night this time of year, and I need to figure out what to wear for my parents' party. My mom is throwing this huge get-together with like 50people, and my boyfriend is finally going to meet them...he's 31 and I'm in college. I have a pretty conservative wardrobe--basically j.crew and gap. I wear a lot of jeans with brown or black flats and cute tops or a cami with a cardigan. I want to look extra cute, because it's the first time my boyfriend and parents will meet. We've been dating for almost 10 months now, so it's a really really big deal. The attire is supposedly casual and comfortable. so what do you think?