Hi everyone

I'm a sophomore currently going through the informal rush process. It's my first time rushing, I didn't do formal last year. At my school, all 16 sororities are doing informal recruitment this fall, and in the past week and a half, I've talked with girls from every house (during the first "open house round") and then visited the 8 houses in which I had the strongest interest. Since then I've narrowed it down to four, attended all the events put on by each, and I still have several more events to go to in the next several days.
Since it's informal recruitment however and I'm not guaranteed a bid, I'm starting to get nervous I won't get a bid anywhere. Honestly, I
do feel like I've felt a solid connection with each house so far, I've had some great conversations with a number of sisters at each, I have a really good GPA, and I think I've made good impressions on everyone. I'm just a worrying type of person though, haha. It will be a real bummer if I don't get a bid. What kinds of criteria are used to decide who gets a bid during an informal rush? If I wasn't offered a bid, could I go through formal recruitment this winter?
Thanks so much for reading/answering, hopefully my questions don't sound too silly, but I've perused these forums and haven't found much about informal recruitment conducted in such a manner (where all the sororities participate).