Problems with the future sister in law?

This probably sounds so bitchy and bridezilla of me. But my FSIL and I both got engaged within 3 weeks of each other and our weddings are going to be within 3 months. She is getting married first, but I got engaged first. Recently my FH and I found a church we really like and now she has decided she hates all the churches except the one we want. It just seems kind of annoying after she has copied us on EVERYTHING. And getting married within a few months of each other I feel like now his family is going to be like "Oh just another wedding at that church" when we get married. I'm really angry about it and I don't quite know what to do...there isn't really much I can do without being a b**ch. Am I justified in feeling this way?