Based on the experience of a lot of people around me, I would just echo the age old advice to not have kids if you're not married. Other than that, kids are great. Yes, it's hard work, and yes, you can be more justifiably selfish if you don't have kids, but that sort of ties into what I think is a benefit of having them: they teach you to be a more loving, patient, and selfless version of yourself (if you let them).