So I Had My Period Either In The Beginning Of

So I had my period either in the beginning of December or like the 2 or 3 week but anyway I lost my virginity on the 22 and I don't know if he cumed in me or not cause I didn't see no puddle in the bed could. But my periods are irregular I take birth control for that so I was wondering do I take a pregnancy test now to see if I could be pregnant?