quota for sorority

Maybe it's true, but it's probably more of a guideline. Yes, some sororities try not to take too many girls from the same school or home town, and maybe three or whatever came from your school last year, but that doesn't make that number written in stone from year to year. A house can set their sites on certain girls before recruitment but can't be certain that those girls will choose them too. Besides, maybe you're one of the girls they are looking at. But, consider these things:
1) This girl, as a sophomore, has never actually been through recruitment as an active. She knows nothing from actual experience. Members don't really understand recruitment until they've gone through it on the other side, and there are always a few actives who never really understand things correctly.
2) She told a mom who told your mom who told you is a great way for things to get lost in translation, and completely depends in what context the subject got brought up. Maybe this girl was trying to shut down the other mom if the mom was being pushy about someone's chances for a bid. Or maybe this girl is saying this to discourage someone away from her house because she doesn't like her, or to make sure other girls are not setting their sites on her house with unrealistic expectations for their chances during recruitment.
No matter what, don't worry about it! There's nothing you can do about it! Just worry about the things you can do something about - get all your recs and bring your best self to recruitment!

OP is a troll posting this elsewhere.

Each sorority has their own private membership selection process. In the name of fidelity, secrecy and loyalty we will not tell you whether your guess is truth or falsehood. When and if you become an initiated sorority member you will become privy to your own org's proper evaluation and consideration regulations. Thank you for choosing to Go Greek.