I am booked in for my 3rd c section at 37w+1 in April. I have had 1 spontaneous labour at 39w (eded in ecsec) 1 medically necessary (pp) at 38w and now this one. My OB will also be on leave over Easter which is why mine is booked early. I am happy with that and trust my ob to help me make decisions that are in both my best interest and baby. If you are worried at all please bring it up with your ob. I will be having steriods before for bubs lungs just in case. I know my date of conception (ivf) but if you fell naturally your dates could be out +/- 5 days in which case 18+5 might be a bit early... good luck op.