Baby shower

Getting nervous about my baby shower. My step mom said she would plan it. She does everything at the last minute. I'm not due until December but I'm the type of person to have started planning already. Last year she waited a week before my little brothers birthday to plan his party. If she does this with my baby shower no one will be able to go. Should I just relax and wait? Or should I say something? I've already sent her my work schedule so she can see what days I have off, since my boss makes them months in advance.