Having a rough childhood is a completely valid reason to not want kids.
Just a disclaimer: I know this may be a controversial post as so many chilfree people are pestered incessantly about "why" it is they don't want kids. As if there's some underlying reason and if you identify it and fix it you will suddenly want spawn.
Not wanting kids becuase you just don't is enough, no other reason neccessary.
However, I do think its important to recognize that for many, (including myself) a good part (but not all) of why I don't want kids stems from my childhood. It was a disaster and I've had to take care of the adults In my life for so long that now as an adult I just want to chill. I will never have my carefree childhood back or make up for its loss but I can sleep in on a Saturday morning, blow my (limited) disposable income on fine cheese and cheap beer and throughly enjoy time with my husband and future puppers.
Just a mini-rant, really, but I just want those of you out there in the same position to know how you feel is valid. Sending virtual hugs 💞.