On this one thing, we actually agree - a woman does need to be given a length of time to discover her pregnancy and make her decision on whether or not to terminate the pregnancy. The "life at conception" position is a purely religions position - one that holds no sway on people who do not follow Christian teachings. Therefore, it cannot be a sound legal basis (even though it might be a sound moral or religious basis) on which to restrict a woman's access to abortion.
You and I differ on 4 weeks. I say 8 weeks is enough, and rely on current medical and biological evidence of fetal development to support this. You think that is not enough and want another 4-5 weeks and you don't cite any biological reason as support. But I think you might be able to find some biological basis to show that in most cases the fetus does not have any form of sentience or feel any pain within that 4-5 weeks we don't agree on. That is our point of disagreement. So, who is right? At this point, I don't think fetal science is exact enough to really answer this.
I do believe the Supreme Court will have to take up the issue of a woman's access to abortion. Roe v Wade is based on the science of fetal development as was understood 50 year ago - that just does not cut it with what we know today. I also think that the 4-5 week time period that you and I cannot agree on will become the focal point of a new Supreme Court decision. At least I think that should be the focal point of any new Supreme Court decision on this matter.