I’m assuming you’re asking in good faith. I found this type of question to be especially controversial due to the legislation against gender-affirming care, especially puberty blockers. In researching further:
As others have stated, cases where permanent gender-affirming care was given, such as HRT (hormone therapy) and GRS (genital reconfiguration surgery), instances of regret are incredibly rare, and almost always predicated by lack of support for the individual. They are far outnumbered by instances of trans people undergoing puberty incompatible with their gender, which is itself damaging and irreversible.
The type of care discussed in this article, GnRH (puberty blockers), has been shown to not have long term consequences, and is only used to delay puberty and the potential long term effects, giving them enough time to make an informed decision about their transition. From the Mayo Clinic:
GnRH analogues don’t cause permanent physical changes. Instead, they pause puberty. That offers a chance to explore gender identity. It also gives youth and their families time to plan for the psychological, medical, developmental, social and legal issues that may lie ahead…
When a person stops taking GnRH analogues, puberty starts again.