My initial reason for not having kids was financial. I think a lot of people have learned it may be better to have children later in life when you can properly care for them. I know many people who’ve had their first child in their late-30s and early-40s. My aunt had her first child in her fifties. That’s not something that was common before modern medicine.
I have always had the idea that I would have a kid if and when I met the right person to share parenting with. That hasn’t happened so I’ve had to put some thought into my priorities. It’s not fair to have a child just because it’s what society says you should do or just because you want someone to take care of you when you’re old. It’s so much more than that and I think people should be more mindful of the responsibilities and long term repercussions.