No, it's OK, I totally understand. You don't have to explain yourself. You've taken on a lot of responsibility, and you have the right to change your mind!
I've never done anything that requires anywhere near the amount of initiative what you're doing takes, but when I was going through rush I changed my mind a LOT. Up until Pref, I had a totally different sorority picked out than the one I ultimately put at the top of my bid card, but that's all right. I'm so glad you're sticking with this and I really admire your dedication, and I don't think anyone has any room to criticise.