Diva cup

A.💕
So I'm going to be purchasing a diva cup for my upcoming cycle arrival in a few days and holy moly I'm nervous to use it! Lol I've read that I should gat the size two since I've had two full term vaginal deliveries but I'm only 24 and quite small/ tight in that area so to speak but the size difference of them isn't much is it? Also, to practice is it okay to try to insert it while not on my period? I want your opinions on it... Can you feel it inside you at all throughout the day? How far do you insert it? I've seen the illustrations of how to insert it.. Does it open up slowly or kinda "pop" open like those little silicone popper toys? Lol