Death House by Carole Avila

Fifteen year-old Adley doesn’t know that something sinister haunts her grandmother’s old mansion, or that it hides in a dark portal beneath her bed. The demonic being—born of a generational curse—kills the first born child in each succeeding family. Adley will die on her sixteenth birthday unless she can find a way to end the evil curse. She meets seventeen year-old Victor Trumillo, a descendant of the original victim, and discovers that only he holds the key to destroying the hideous creature. Victor and Adley want to end the curse and save future lives, but will they succumb to fear just when they may have discovered real love?