[Pirouette]

Aerylle-lots of sorority girls have jobs during college (including myself). It wouldn't be the first thing to advertise during rush (don't say "Hi, I'm Aerylle and I have a time consuming job!") but if they ask about your involvement, mention it (something like "I was involved in this club and that club in high school. I want to continue my involvement with that club in college but I also have a part time job. Being involved in high school has helped me learn to manage my time so neither activity should affect the amount of energy I put into being a sister.")
Just let your sisters know ahead of time if you're going to be missing an event.

Good luck!
PS, ditto the planner. I've been out of college for years now and I still refer to mine like a bible.