Is it more selfish to have kids when you want to train to become a commercial pilot?
Life is full of compromises. Some aircraft take loads of passengers and loads of runway (A380), other can take off in almost no distance, but carry a lot less load (Cub).
Anyway, about a third of marriages end in divorce, so you'll hardly see the kids anyway!
(In other words, do what makes you and your spouse happy: that's what will keep the kids happy too)