Positive for Strep type B.

My OBGYN took a blood/urine test last month and somewhere in the results it said I was positive for Strep B and that I would have to be on antibiotics when I went into labor. Is this a common thing? Should I be really worried about it? I am a FTM and I am only 13 weeks (tomorrow) I just don't know what to make of what the doctor told me. I asked her and she blew off the question.