Baby shower blues

Okay I'm just kind of venting and I want to make sure I'm not in the wrong for feeling this way. So my mom is throwing my baby shower which I am completely grateful for. I am due feb 18th and my mom wants to throw the shower January 14th. The problem is, that day is my cousins birthday and she will be going to the shower. My mom wants to make it a baby shower/birthday party for her. Am I wrong or selfish for not wanting that? :( I see her like 4 times a year, we get along but we're not super close. I only text her on holidays and her birthday. I asked my mom to just move it to a week before and she said no that interferes with everyone's schedule. She said not everything is about me and I know that but I don't think it's wrong for me to not wanna share this day with my cousin when it's two completely different celebrations. She's turning 23 btw