It's hard to put this into words, but, I feel (this is only my personal opinion) that the fetus is the beginning of a life. If that life is not allowed to proceed to full term, this child- to -be will never be. For example: if you abort your fetus, then get pregnant later on in life when you are ready, that child (the second one) who is born is not the exact same child who would have been born before. I would feel that the first "child" was denied life, and never will be. No two people are the same. Does that make sense? When I met my birth-son, he thanked me for letting him live. It is impossible to describe how that made me feel.
We all have free will to make our own decisions, we just have to be able to live with them, and live with any consequences there may be. Go with your heart.