Am I being selfish?

I really want a baby. My fiancé thinks we need to wait a bit longer. The problem is my mom is really sick and I want her to be there when I have my first child. My father died when I was 6 and I don't have any siblings so it has just been my mom and I for the longest time (I am 22 now) in addition all of my family on my mom's side stopped being able to have kids at the age of 25 and we all started our periods younger than 10. I ended up crying yesterday because of how much I want this... but at the same time I feel selfish. What do you think?