I went through informal, fell in love with one house and never got asked back for pref. I wrote off the other sorority I went to because I didn't feel a connection initially.
Later on, I emailed their recruitment chair, asked about COB and they took me out for coffee and then I found they'd signed a bid for me before they picked me up.
COB is a wonderful, informal setting. I definitely think you should try for COB, and if not, it sounds like you've already carved a niche for yourself on campus. You really do have the greatest attitude and any sorority would be lucky to have you