I started my HT journey 2 months before my 37th birthday, starting with the consult and then the testing. It turned out I had a high FSH (13, ideally should be under 10), but my RE was not concerned. He just thought I wouldn't be a stellar egg producer.
And I wasn't.
First cycle (age 37.5) I only produced 4-5 follies total. We cancelled prior to ER. 2nd cycle (still 37.5 yrs old) we retrieved 7 eggs, 6 fertilized and went to PGD. 1 normal girl (no MS).
As with everything else HT, you just never know what will happen.