Spectra S1 Breast Pump Confusion

Nipple size likely to increase slightly as milk production ramps up at the start but also likely to decrease after milk supply stabilises after a few months. So I’m going to measure just before due date, and order a size based on that. Then measure again when the milk comes in. 10mm sounds small- might not be correct? Pumpables website says 17mm is most common. Suggest printing out a nipple measurement tool online to measure. Great that you realise the 24mm is too big. I didn’t realise my 24mm was too big for my first child and would likely have had better yield if I did!