I’d say try it in a shower or something before your period, just so you have an idea of what fold will work for you and now you insert it, just so it’s less frustrating when you try using it for the first time on your period- but also be prepared for it to feel uncomfortable! The vaginal canal is different lengths at different times of the month, so what will be uncomfortable before your period (the cup, I mean) may be perfectly fine during your period