It's complicated, see this article for more info: https://www.bbc.com/news/health-51463488

Very high if they’re frozen when the woman is <35.

The answer is that fertility only goes down. If you want to ever get pregnant, you should begin at least taking initial steps today rather than waiting.

Yes, I think GP is noting that egg quality declines somewhat exponentially, rather than linearly.

ok, here’s your accurate answer: every situation is different and predictions are impossible.