It's a normal bacteria that a lot of women have in the vaginal/anal area. It can get passed to baby though and cause issues if not treated. That's why they test for it. Now that they know you are positive for it, you will receive antibiotics during labor that will prevent it from being passed to baby.
its only dangerous to the baby if it's untreated or undertreated during labor. you will get multiple doses of antibiotics in labor (preferably Pen G every 4 hours as long as you aren't allergic) the initial dose should be a loading dose (double strength) studies show that the loading dose takes away 25-ish % of the risk and by the 4+ dose its like you tested negative
if caught early no worries. a girl I went to school with was tested at 27 weeks not 37 (or 36) and she was neg. But when she gave birth to her son she actually had it and no one knew it and her son died 2 days later.