How formal is Pref. night?

[Aerylle]

I know it changes per school, and per sorority, and per year, but my school's website only shows two dresses on the website which doesn't give me a very good idea.

I assume by 'formal' it means cocktail dresses, not prom-like dresses.

I have found a dress that I love, but I keep thinking it might be too formal. It is a form-fitting bubble hemmed pink dress.

It's the same material most prom dresses are made of (the shiny material), but it short and more party-like.

Here's my questions:
1. How formal was your dress? ((A link to a similar dress would help if you can. If not, it's cool. :]))
2. Where did you find your dress?
3. Is the dress I described above too formal?
4. Is it best to stick with neutral/simple colors, or are bright colors acceptable?

Thanks girls! If there are similar threads, just link me. :] I've searched around and can't find exactly what I'm looking for (but I tend to overlook the obvious sometimes. ha ha)