What's interesting to me is that you (and me, and our kids) were called a "fetus" the second before we were vaginally discharged somewhere between 38 and 42 weeks (I'm guessing, which is the normal "full term" definition I believe). The 5 minutes before you were born you were a fetus and not a human being; does anyone really believe that?
I think that is the problem you are addressing-- there are no clear lines of demarcation or thresholds which we can point to as black and white, right and wrong. I do think there are others who don't subscribe to my thinking (which is all abortion is murder), who can try and make arguments very early (basically before a heart beat) that seem practical and ethical if I put myself in their shoes and their lacking of my values informed by certain faiths and beliefs, and can accept politically that without agreeing with it morally.
But there are still obviously some differences and it probably defaults to most, sane people's "Roth test" of "I know it when I see it" meaning that aborting a 35 week "fetus" or 38 week "fetus" or 30 week "fetus", seems to be playing with semantics at best, embracing euthanization at worst.
That said, I am honest about the dilemma of abortion being made legal. Of course people talk about the health of the mothers/baby who do illegal/blackmarket abortions, but also in the sense that many, many (if not most) of the people getting abortions are in some ways being responsible. They realize they are poor, can't afford a baby, can't raise a baby well, won't be able to give the energy and resources and love into a baby to optimize and maximize their potential or just are honest about their selfishness to not want to share limited resources and time with a baby. These poor, unprepared, unwilling, and generally unable people would be bringing untold lives into this world to be an anchor around the necks of the already choking middle and upper-middle class, but that being said; I'd choose paying more taxes and sacrificing my quality of life, if it means saving babies from being cut down in the womb.