On the "bright side", if there is one, teenagers below 16 or so generally don't go all the way with transitioning. Obviously there are some places that allow/have not illegalized SRS and "puberty blockers" for minors, but a lot of the ones just doing it for attention tend to settle for "social transition"--i.e. changing your name to something retarded like Cal or Jayden (pooner classics), whining about pronouns, dyeing your hair an ugly color and dressing like a middle-aged man.
I'm legitimately surprised to see it being debated here whether medical transition can be "sometimes a good idea". There's not a ton of good research on this yet, since the trans epidemic is kind of a recent phenomenon and there hasn't been time to examine the medical effects that transitioning has over time, but one study/survey I did see found that people who transition feel good about their transition for only the first 5 years or so. After that, their mental health tends to take a pretty sharp dip that never recovers. These are the troubles of peddling irreversible chemical and/or physical alterations (to healthy bodily functions!) to people who obviously have greater underlying issues. Lots of girls who poon out were previously struggling with eating disorders ("too much fat makes you look more feminine, time to starve myself"), autism, mental health disorders, or just downright bad social skills. Transition answers none of these problems.
As a last aside--girls or women who take T almost invariably develop early-onset osteoporosis, since estrogen is what helps maintain bone density. Developing this condition can and often does mean chronic pain, for young people who were otherwise physically healthy. It's a bad idea in general to load your body with a hormone you just don't have the receptors for. And although puberty blockers are touted as reversible ... once you've missed that window, it won't come back. So people who have had that kind of treatment tend to stay both physically and mentally underdeveloped into their adulthood, which only makes things more difficult.