AIO: Wife Not Going To Stepson's Wedding Because Her Daughter Has A Softball Game

I'm a 48 y/o man married to a 41 y/o woman. She has 2 daughters (10 & 11) from her previous marriage, and I have one son (27). My son is getting married in June and we of course made plans to be there. Yesterday she told me that she wouldn't be able to go because she just found out her daughter has a softball game that same day. AIO to think that this is pretty ridiculous and screwed up? Is a softball game more important than my son's marriage? I haven't talked to her yet about how I'm really feeling because I need to get my thoughts together & I don't want to sound like a complete asshole, but I'm really pissed about this.