Breech baby at 36weeks

Hi mummys ! Is there any of you who experienced breech baby at 36weeks but baby turn head down the following week ? I went for my check up yesterday and the doctor was confident that i will be going for a C-section and thus did not do any vaginal swab on me. But what happens if baby decided to turn her head down and im ready for a normal delivery but i havent do any vaginal swab ? Im afraid if i have GBS and it will affect my baby.