I would recommend having a backup dress just in case things go wrong. Making formal wear is a lot more difficult than making everyday clothing. You do have a lot of time before your wedding though, so if you do decide to go this route I would start ASAP!
My friend got married last June and she made her dress! It was so pretty because it was unique! She loved the fact that she made her dress and that no one would have a dress like it. I say, if you have the experience, go for it! (:
I say go for it! I think people recommend not making it because there's almost an obsession for some people to have the perfect wedding. If you've made a dress before and practice working with the fabric you want to use, I don't see why not! I was going to make mine but I ended up finding an inexpensive dress.
I know this is late but I'm going to make my dress, too. I debated buying a serger to speed up the process but will likely use machine I've been using forever because I'm used to it. I'll start working on it in March when my work events start slowing down.