I found a golfball sized lump dangling from my girlfriends vaginal walls 3-4 inches in in?

yesterday, i fingured my girlfriend before we had sex and i asked her, what is that ball inside her vagina, she didnt know, her fingures were to small, so, when i grab my middle finger and digg it deep there is a dangling ball inside her vagina shaped as a golfball about 3-4 inches deep, dont tell me its the cervix because i know what that is and it is farther up, and her g-spot is a pea sized bump under her pelvic bone on the roof of her vagina, i have been researching for hours,i need an answer, its only connected by a little piece to the roof of her vagina, not the walls, i was her first at intercourse and she has not gotten a pepsmeere(or whatever u call it) or whent to a gyno, i never told my girlfriend because i might freak her out, but i think she has a cyst or cancer and im very scared for her and i need an answer please?