Your argument works by creating your very own definition of what it is to be “a human” to then say “you can’t kill a human”.
Redefining the meaning of the words used and then claiming that you’re right because there exists widelly accepted moral rules which use those words - but not as you defined it to be - isn’t actual logic, it’s wordplay.
The foundation of all your arguments on this is a “trust me” definition of “a human”, provided as an unchallangeable, undetailed and unsubstantiated axion - change that definition to, for example, “a human is somebody born from a woman” and that entire argumentative structure of yours collapses since in that alternative definition until the moment of birth a fetus is a thing, not “a human”.
So you pointedly bypass the actual hard part that matters the most and were the main disagreement is - the whole “when do human cells stop being just cells that happen to have human DNA and become ‘a human’” - with an “it is as I say” definition on top of which you made your entire case. That’s like going “assume the sun is purple” to make the case for painting the walls of a house with a specific color.
All this would be an absolutelly fine and entertaining intellectual game, if you weren’t defending that people should go to Jail when they do not obbey the boundaries derived from your definition of “a human” and treat as “not a human” that which you chose to define as “a human”, which is the logic of the madman.