Don't fret darling, your absolutely right... I have way too much time on my hands ! A dress is actually a really easy thing to find for any party. You said your going to a sweet sixteen but these rules could apply for a bat mitzvah, or a quince or whatever. The only thing is what type of dress and what price range. I'm going to pick some stores online, but they all have locations here in one of the malls (: Since you are going to a party, I'm sure you don't want a lengthy dress or one that's too dull because no one wants to blend in. Color is for sure key when picking out a dress. When shopping online its always awesome to read the reviews and see what people have to say about sizing and what not.
Silence & Noise Strapless Tulle Hem Dress is an online exclusive on Urban Outfitters, and I love the color. It's a great length for a dance party and you can wear it with or without the tights shown in the picture. It does have pockets which is always something cute. The reviews on this dress say its a great dress and fits like a glove if you get the right size. One thing I will point out is that people claimed that if your chest is larger you should go a size up for it to fit. Pair it with a belt or some cute jewelry and it's a great party dress. For makeup I would go with like a smokey eye since it is purple, but the dress does come in black if you don't like this color.
Disco Sequin Dress on Forever 21 online will for sure catch peoples attention at a party. I think its a super fun dress and its also a good length. I'm not so sure I love the gold color on this girl, but with darker hair it would deff work. The straps are adjustable and the bust is padded, which are both pluses. There aren't any reviews with this dress but it is available in stores to try on. For this dress I would wear it with some bangles and a simple shoe. Tights or anything would just draw attention away from the dress. For makeup I would for sure play up your eyes with a gold glittery shadow and you will be good to go ;D