My 6 year old female has never shown sexual maturity until now, and needs to be spayed

I saw an emergency vet about two years ago that did x-rays on her to check her bone density. All that was good, but they also found that she had no active reproductive organs. My friend who had a female beardie was shocked to hear that I had never seen Billie lay any eggs or have binded egg complications. She was just an infertile enigma. But my new vet felt some hard structures in Billie and did an ultrasound that showed she had calcified eggs in her OVARIES. So idk if that means she just took a really long time to become sexually mature or if the last vets I was with just did a bad job. Either way, she’s now scheduled to get the eggs surgically removed and spayed. I’ve heard it’s a risky surgery, but my vet has told me she’s done plenty of those surgeries before and it always ended fine. I’m just so confused as to when those eggs even appeared, and how long they might have been affecting her. And it’s not like this is the first time in years that I took her in to the vet, she’s been having regular checkups for months now and it was never detected