pledging alpha phi?

Then don't go aphi if your "kinda worried" and what makes you think they would offer you a bid? I'm not aphi btw but know several really well rounded girls who are. Every single sorority here has party girls, just like they all have girls who focus on grades or volunteering or leadership. Each sorority is made up of different girls from different walks of life, why don't you just wait until you actually go through recruitment and see which house you connect with.

At the end of the day, Alpha Phi's reputation here is not the strongest. While there are other houses here that are known for academics, involvement, pageant queens, etc. Alpha Phi is known for their "party girl" reputation. A lot of Alpha Phi's are very social, thus why it seems they tend to go out every night. And while, yes, every house has their handful of party girls, Alpha Phi has a lot more than other houses.
However, just because Alpha Phi has a lot of girls that like to go out, that doesn't mean they don't have girls with other interests. No matter what sorority you join you will be able to find friends with the same interests as you, because I mean a group of 150 girls cannot all be the exact same.
If you're worried about grades, I suggest you stop making assumptions about houses you haven't even been inside of before and girls you've never met, and instead go and try to study.

Public Instagrams tell only part of the story. I know plenty of Alpha Phis who have difficult majors and are busy making Dean's List. So don't generalize that "all" are party girls.

And what make you think Alpha Phi will give you a bid?