Please Help I Need All The Help I Can Get

Okay, so here's the stitch. I'm getting an apartment with my dad soon, because his mother just died and he needs to get out of this town, and I need to go with him to help take care of the kids because he works 12 hour days. But the thing is, I'm over 18, so I need to be on the papers. Which means I need a credit score or at least 600. I do not have a credit score, I'm 18 and have never had a credit card. But I can't get a credit card without credit, the only people that can get beginner credit cards are students, which I am not. What do I do? Please help