Renting an apartment? ?

I live in Houston TX. I am currently 17 and about to turn 18 on July 26. Can I rent an apartment now or do I have to wait? And I know everyone says you have to have a good credit score, what does that even mean? I mean I have a good job and I'll have a roommate. But how do I get this "credit score"? I don't even own a credit card, is that going to be a problem? Please tell me everything I need to know.