Tensei Majo wa Horobi wo Tsugeru

On her eighteenth birthday, shut-in Sena Shirai gathers her resolve and steps out into the world for the first time in a long while—only to be hit by a truck! Reborn as a witch in another world, she is only able to master two spells: Explosion and Destruction. With the nearby villagers fearful of her powers, she resigns herself to an isolated life once more...that is, until a mysterious boy collapses on her doorstep! 

(Source: Yen Press)