rec letters?

Yes, a girl only needs one rec letter for each of the 13 sororities. You have almost 3 months to do this. You can do it! Ask on social media, ask family, ask family friends, ask friends of friends. If all else falls contact your local alumnae group. It sounds like a lot, but it's really not.
When they agree, it is up to you to provide everything they need for them to be able to write and submit this letter for you.
Have a good sorority resume, there are a million examples online
include a nice headshot photo
Include a STAMPED addressed (to the sorority) envelope for them to submit this letter.
Get their mailing address to send them a hard copy of what they will need and to write them a thank you note for doing this for you
Make it as easy as you possibly can. Most alumnus are happy to write a letter of recommendation for you, but don't have to. Be grateful that they are willing to

Obviously someone who has gone through it or researched how to do it right!!!