So I'm confused..

I called to make my first prenatal appointment, and the girl on the phone asked me the first day of my last menstrual cycle, which was Dec. 6th-10th, and she says I'm 5weeks and 1 day. Those calculators they use to determine weeks is by a regular 28 day cycle. I have a 37 day cycle, so I'm actually 3w7d.. Not 5w1dI found out I was pregnant 4 days before my missed period and the lady on the phone was telling me my period was supposed to start on the 6th (28 cycle).....