You want a minimum of three for a game like this. Four or five would be ideal. Plus you as mother of course.
Effekt - A fan podcast celebrating Swedish RPGs including, but not limited to: Alien; Coriolis; Forbidden Lands; Symbaroum; and Tales from the Loop. Featuring discussion magazine episodes and Actual Play recordings. https://effektpodcast.org/
I'd actually advocate closer to 3/4. Horror is more threatening when you haven't got loads of people to provide 'comfort'. Also fewer players makes it more likely you'll get through the scenario without someone breaking immersion.