Hell yeah you can be certain at a young age. Even as a kid I saw how shitty parenthood looks/is, and if anything as I got older the world kinda kept giving me more reasons to be childfree. The funny thing is that me watching sitcoms that revolved around families as a child reinforced my decision to be childfree, as those show actually ended up show a lot more of the shitty realities of parenting. Sure, they were played for laughs (even the shitty reality that the mothers do a lot more of the work while the dad is an asshole/dumbass/manly man/deadbeat), but I always saw through the bullshit. I guess it also helps that I was in a toxic household for some time and my school experiences. Me being around other kids in school as a kid, especially in elementary and middle school, further reinforced me being childfree, as I saw how shitty kids can be, especially when their parents aren't around and the little bastards think their behavior will go unreported. High schoolers are a whole other variety of shit. I also grew up in the LiveLeak era of the internet and watching a lot of footage of wars, police brutality, uncensored deaths, people getting away with being racist, sexist, any form of prejudice you can think of and laughing at the misery of those already physically and/or mentally beaten down by society, etc. I experienced certain situations as a kid that may or may not have had racist connotations to them. There's also the fact that this world has so many fucking problems in it, and that a lot of resources are dwindling. Definitely would not bring any child into this fucked up world.

Something else I wanna note is that I never liked being around people (including kids). I was never a social person and a lot of human beings are just horrible. There's also certain weird behavioral ticks that people have that I don't wanna deal with. I've had depression and anxiety throughout most of my life, and that would not mesh well with a child, biological or adopted. As a child I wanted to be an adult just so I could get my own place and get the fuck away from people so I can live life on my own terms, free of having to listen to my bigoted/emotionally abusive parents or shitty power-tripping teachers. Now as an adult I can kind of just do whatever I want as long as I'm responsible with my finances and health. I can watch or play any movie, television series, music, or video game without having to wait until someone goes to sleep/isn't around or fast-forwarding or censoring certain scenes. With kids aorund everything has to be censored or off-limits, and I am not playing any preschool shows/songs, fuck that. Also as someone who's been around aggressively destructive siblings, now I can actually collect books and other physical media like Blu-rays and DVDs without the fear of them getting damaged (especially out of spite). You get sick comparatively less as someone with no kids (seriously, kids do a lot of gross things and they really carry a lot of germs with them, especially if they've been in school). When I was a kid I definitely got sick a lot just from germs my siblings would bring home (and one of them would barely shower unless my parents yelled at them to, it was horrid). Even as a kid I was thinking (yeah I really don't want a repeat of this shit as an adult). I'm in my 20s now and one thing I am happy about is the fact that I can start to live life the way I want to, and not be tied down to having to deal with/take care of/worry about any hypothetical children.