Yes, it should be legal. We should not bring babies into this world who are unwanted. A full 49% of pregnancies in the US are not planned. Unintended pregnancies are common among poor women and teenage girls who must raise them in poverty. This increases the chances their children will turn to a life of crime. Abortion is an effective way of preventing overpopulation.
It shouldn't be legal because girls should not be in bed with boys in the first place if they are not ready to be a mom.