I am a Classics major, so you can edit your question if you have any more questions about mythology.
First of all, Ares is not nearly as cool as he sounds. Ancient Greeks hated him, and were afraid of him, and he had no human children, just Demos and Phoibos (Fear and Terror) who accompanied him on the battlefield. You see, Ares is not the god of war, he is War. He is violent, unpredictable, dangerous. And this is not something you want in a god, or in a father, for that matter.
Tricking human women to have sex with them was what Zeus did. Ares is uncapable of subtlety. He would have raped your mother and probably killed her, so she wpuld remember an experience like that.
Also, demigods have incredible strenght, so if you can't lift a car with your bare hands, you are not a demigod.
But you can still study Greek mythology, which is way cooler.