Pregnancy test

How long should I wait to take a pregnancy test? Every time me and my guy friend had sex we didn't use a condom but he pulled out before he came. I am not on the pill. The last time we had sex was August 28-29 and I should be getting my period within a day or two. My friend recently had a pregnancy scare with a very similar situation and I want to get a test just to be sure but this whole thing is new to me.