It’s possible she just has a tiny clitoris.
Kind a like a guy with a very small penis. I can't imagine that it would be an issue but it appears it is. Remember women don't like total attention to the clit. It must be random and light until she is ready for full on. If you go right to her magic pearl and nothing else, that will be a turn off of sorts. Try teasing it and run your tongue towards it and at the last second avoid it...will drive her nuts!

Random attention is the key. When she is ready, try doing the A, B, Cs on her with your tongue. Seems to do wonders.

Above all, stress to her that you simply enjoy having sex with her and being intimate with her and couldn’t care about if you or her...Mostly you even reach climax. This is kind of a false statement, but you must get her to stop focusing on reaching orgasm and focus on just enjoying being together, etc.

Once that state has been reached, she will come...sort to speak!

Is she on any medication that alters her moods, for depression, anxiety, etc. Too many times I have seen this over looked as many medications simply shut down the orgasm response in the brain.

Good luck.