Sorority Questions

I'm going to be going through rush this fall, and I have some questions that I could use some help with. I was talking to this one girl who used to be in a sorority, and she was telling me how you can't miss any meetings ever. I thought that the sisters would be more understanding though(like sometimes you have to work and can't get your schedule changed.) If i joined a sorority it would be one of my top priorities(next to school)but the same girl also told me that the sorority should come first. I don't understand how that could work if you have a job(the purpose of which is to pay for the sorority)and the sisters get mad when you have to miss a meeting just so you could get money to be in a sorority. Is this true?