COB?? Spring rush??

I’m a freshman and I did not go through rush since it was online and I just didn’t see the point in still spending the same amount of money as required every year just to not get a lot of what I was paying for out of it. However, I am very bored on campus and honestly do want to maybe be apart of a sorority. I have friends that did just go through rush, but it only really went “well” for one of them. Some dropped, some got chapters they didn’t like and wished they’d dropped, etc. I’ve heard them mention COB and spring rush and I’ve also heard of the COB during spring being different than it will be for when it opens up now. I’m just confused and was wondering how the rush process works in the spring and if there’s a difference between COB like now and COB in spring? Do the same sororities that do COB do spring rush? Also, which sororities participate in them or will you not know for sure until it happens? Not to be that girl, but I really don’t want to get stuck in a sorority that’s not amazing just because it was the only option available to me. Thanks in advance to anyone that explains or helps me!!