Do you really have time to do all that crocheting? Is that the pressure you want to be under as it gets close to the day? What if it becomes clear you aren’t going to make it, and you have to make alternative flower arrangements at the very end? Not relaxing, and you’ll be under enough stress as it is, I would think.
I don’t know how fast you are, nor when your wedding is, nor how many arrangements you need, nor how much time each will take to make, but if you are going to do this, you better time it out and make sure you have enough time set aside to get it done with a month to spare. You are not going to want to be making these things at the last second.
I would say, purely on time management alone, that this is a stressful idea at best, and quite possibly a really bad idea. You have no idea how much other things are going to be keeping you busy as you plan your wedding. You can’t possibly imagine. If anyone really knew what they were getting into, no one would actually get married. And that’s just with respect to the ceremony.
Besides which, in my opinion, fresh flowers look so much nicer. Sculptures (and that’s what your crochets would be) symbolize something static, and I don’t think that’s what you want for your wedding. Flowers are about life and beauty. They are much nicer.