I am curious can you pass a background check, if you are under 18?

Assuming you have no record, you can pass a background check, regardless of age.

Thanks, one more more question how do background checks work exactly?

Well my husband had to have a background check before he could join the military. You answer some questions, they check your criminal record, and in his case, had some people go and talk to his roommates, buddies, etc. Of course, this is my only experience with such things, and it was the US military, so it might have been a little excessive.