menstrual cup

i recently bought a menstrual cup and i started my period today and i was excited to use it. at first i couldn’t get the cup in at all and i was getting frustrated. but then i used some lubricant and i was able to get in in about half way before i felt a pain and had to pull it out. i have used tampons in the past but they have started to feel uncomfortable so i wanted to switch to the cup. i am a virgin and have never had anything in my vagina other than tampons if that makes a difference. i really want to be able to use the cup and now i’m nervous i won’t even be able to have sex in the future because of this pain. i am just wearing a pad right now and my vagina feels sore. i am using the lily cup one.