Help Making a Decision?

Hello all,
Since not knowing a thing about menstrual cups a few days ago, I've learned a lot while reading from this site and others for literally hours and hours. However, now I'm overwhelmed a bit at all the different qualities/user experiences! At the beginning of my search, I purchased a small Diva Cup, but just sent an email on amazon asking for my order to be cancelled because I'm not sure it'll be the best kind.
I am 20 years old, occasionally use tampons (regulars, maybe 2 or 3 times/cycle), not sexually active, and (I think?) I found my cervix to be around 4.5-5ish cm while menstruating. I was concerned about the Diva being too long, which seems to be a common experience. If my order can be cancelled (or if I suck it up and shell out the cash for another cup), I was thinking about the smaller Lunette?
In short, which would be a good, middle-of-the-road choice that's most likely to work best given the rough guidelines and my inexperience?
Thank you so much,
Sincerely,
Very overwhelmed and indecisive