Personally, I think it should be up to the woman. As others have said, for anyone who has no testicle function anymore it's basically as simple as withdrawing female HRT. Possibly, though I don't know for sure, lowering the dose to menopausal levels might equally mimic what it's like for a cis woman on "normal" HRT.
The closest parallel in cis women is those who've had "surgical menopause" happen younger than the typical age - ie, ovary removal, triggering immediate complete cessation of estrogen production. (Except for the adrenals, of course.) Many, though not all, of those women choose not to discontinue HRT when they do reach typical menopausal age.
I'm considering it myself, at least right now; I'll have to see how I feel in ~15 years when I'm close to the usual age, but at the moment it seems kind of nice to imagine getting to have at least *one* of the "standard female life cycle rituals" happen at the right age. Of course, I'm already on a menopausal dose of HRT (not listing actual dosages, but it's within the range prescribed to cis women) so to get truly menopausal I might well have to go cold turkey.