Not sure I can offer much advice, but wanted to chime in with an “I hear you!!”
I am also a mid/late 20s female returning to school. Unlike you I have NO science background, so am also expecting to take all of the prereqs in a formal post bacc program.
Your comment about choosing between work and family life really resonated with me - that is something I have been struggling with. I would also like to have kids in my early 30s, but at this point, I can expect to complete my residency in my mid 30s. I’m also dating someone, but we’re not far enough along to really be talking about those kinds of timelines and life goals, so it remains this intangible, looming concern! (Never mind he freelances and travels a lot for work, so couldn’t be counted on for providing stability for these hypothetical future kids!)