My future mother-in-law is going to someone elses shower on the day of my shower. Should I be offended?

My FMIL old dance teacher is having a baby shower the same day as I was going to have my bridal shower. The other girl is around my age and very sweet. She originally was not going to do a baby shower because she was moving out of state. When I found out that she was coming back to town to have a baby shower I was happy for her and sent her a message to see when she would be in town thinking that I could co-ordinate the two showers so that my FMIL could go to both. She didn't respond to me and then a week later I tried to pin down a day that my FMIL could go to and she told me that she has her brother-in-law's graduation, is out of town for work (which is true), and she is going to the other girls shower. She told me that I should do it while she is gone and she would skype me. I started planning my wedding before the other girl was pregnant, have been with my fiance for over eight years, and tried to coordinate both showers before the date was picked. Am I justified in feeling upset? I probably won't say anything because I don't want someone to go if they would rather be somewhere else, but I also don't want to change the day for no reason. I also don't really want to skype her in because it just seems weird to me. What should I tell her?