Against my better judgement, I'm going to engage in good faith here.
What exactly do you mean by "like this"? There is nothing about this girl altering her body in the article at all. In general, people her age transitioning is mostly social (changing name/pronouns/aesthetic) and getting care from specialists who are doctors who know more than you or I or the average person about what might help the person in question. At a certain point puberty blockers come into play, which is not really altering the body as it is preventing possible harm to the child by forcing them to go through a possible traumatic experience that we can prevent. This gives the person additional time to ensure they are confident and happy with their decision. Puberty blockers are widely studied and if a person chooses they can stop them and the puberty of their assigned sex will proceed as expected. In the case that they decide to proceed there is an extremely small regret rate and the majority of that regret is because post coming out the person was not supported by others.
Your personal experience has really nothing to do with her experience or truly any other trans persons experience, seeing as you are clearly not trans. Your thoughts on these people are irrelevant as they and their literal team of doctors likely know what's best for them far more than you ever could. There is paper after paper and organization after organization that you can look into with stats and figures and actual evidence, so I hope before you go around assuming your personal experience is somehow more relevant or accurate than that of the majority of all trans people and accredited medical professionals, you spend some time actually bothering to look into it. If you truly believe that time will tell, then I have great news for you because we as a society have known about trans people forever, and time has indeed already told, over and over and over again: https://pmc.ncbi.nlm.nih.gov/articles/PMC8099405/