At birth? Why? That makes no sense. If you're going to use personhood as the basis for your stance, it should come when the qualities that define people as persons appears, no? With the nervous system, maybe? How does birth make ANY sense?
You even go on to say that YOU wouldn't abort after the first trimester... why is that, then? Perhaps because you don't actually believe it's not a person until birth?
Er... what? I think you'll find that an unborn baby at nine months IS a person legally. You can't abort at that stage legally.