Nipple Rulers, Flange Inserts Sizing Measurement Tool for Breast Pump, Soft Silicone Flange Size Measure, Nipple Measuring for New Mums/Women

You can order a cheap sizer, check before and after you pump as they may change slightly. You’ll want to go with the higher number. https://a.co/d/02bcCB1Y Local birth centers probably have a breastfeeding circle or support group. You could try going there for sizing or tips!