It's a good point to recognize that it might not fit; in every other area of life, people's desires don't always match up with what suits them. So there's no reason to think it would always match up here.

But how do you know that what didn't work for you always won't work for others? Amanda Roman describes it working pretty well (especially in the comments to Samantha Shelley).

And there are yet other people who transitioned, detransitioned, and then transitioned again before they felt that things were right.