This notion that women can’t get pregnant in their 40’s is nonsense.
Many generations of women have had babies in their 40’s.
Many of my family members and friends were born to mothers in their mid-40’s.
Many women I knew in my generation also gave birth in their mid- to late 40’s, but NOT with IVF. They had surprise pregnancies.
Usually, couples try to avoid pregnancy in those years, but not because pregnancy isn’t possible.
The only couples I’ve ever known who had trouble conceiving were having trouble in their 20’s.