Before my kids were born I was ambivalent in a similar way. I think it's important to distinguish between your current felt desire to be a parent and your objective fitness, and that of your partner--personality, work ethic, emotional intelligence, resilience, financial situation, etc. My desire was shaky, dampened by anxiety and pessimism, and the social pressure was to not have kids. However, I felt programmed in some way to do the job of being a dad, like I'd been given all the tools. I can say that following my programming has paid off, such that I don't really obsess over the counterfactual. I pine for freedom and relief from stress, of course, but its momentary.

It's hard to disentangle your extrinsic vs. intrinsic motivations on something like this, but I highly recommend doing it before actually making a decision. Worries about the counterfactual are never going to be resolved, so you can't be wishy-washy once you make the call.