KitKat...you must have a lot of emotions swirling around inside you right now with the bid situation. I do echo to you what other members have been sharing on the boards and also encourage you to try it. Your pledge class sounds like a very great group that already shares some of the same "vibe" considering where you went to prefs.
My cousin is a Chi Omega. She was very bummed they didn't have Chi O at my school, but since she was older she always got to do things like joining a sorority first, etc. I am actually glad we had different affiliations because like you said, you have followed in her steps. And, now you can have a more Panhellenically diverse family
!!
Chapters and the tone of the membership change after time. Think about this...if in the present day your cousin was a PNM maybe she wouldn't have picked her respective group because the same composite isn't there...not saying that there is any "right" or "wrong" group.
Now is the time for you to be able to make your own road!! Enjoy pledging and getting to know your pledge sisters and your new Chi O sisters! If you and your cousin remain close after you graduate and are able to be active in an alumnae Panhellenic together down the road that would be a great sorority experience for both of you!
But for this time, enjoy YOUR time and make your college and sorority experience YOURS!
Congrats to you and CHI O!!