My Vagina Hates Me!

I never thought I'd be making a post about this, but I'm at a loss. The opening to my vagina is abnormally tight, which is starting to cause serious problems. I've been to the gynecologist about it, and all she had to say was 'Well it's not vaginismus or your hymen at all! Your vagina is fine inside, it's just the opening that's tight!' with a big grin and sent me on my way. It didn't help at all. It doesn't matter whether or not my actual vagina is fine if I can't get anything in there! It's always been like this, which was fine when I was 15, not sexually active (solo or otherwise) and only used tampons. With a bit of work, I can fit a regular sized tampon inside, but I really want to make the switch to a menstrual cup, and I'd like to have kids one day! I've tried stretching the opening with both toys and fingers when fully aroused in a squatting position for the best chances and nothing! Can't get more than my pinky finger in. Any advice?