diva cup sizes?

I Am wanting to get a diva cup finally after having my son vaginally almost 2 years ago. I was leaning towards the smaller one eventhough it says the larger one is for anyone over 30 or who has given birth. I am 23 and had one vaginal child birth delivery. I have always hated tampons and just feel like the larger diva will be too big? Any guidence or suggestions would be very helpful.