I'm very glad that I did not follow the course of my life that I had thought it would be at 16/17. It's likely teenagers with gender dysphoria do not have a grasp on their identity or sexuality, and therefore it's best they wait until they're older. I personally feel even 18 is a bit too young for medical transitioning. When I was 18 I got what I thought was an amazing tattoo that I put a lot of thought into and thought I wanted it for life. Now, at 27, I'd rather not have that tattoo. I can't imagine making a decision to sexually mutilate myself at that age and grow up no longer feeling that way.
But the statistics do not agree with you. The statistics show that the majority of people who transition will not detransition, and if they do, it's usually because of societal pressures, and oftentimes, they will retransition later.
In my personal experience, of the >10 people I knew who said they were trans at 14-16 years old, not a single one has detransitioned or changed their mind 8-14 years later as adults.
But who cares about my personal experience... Let's provide actual statistics.
A UK a survey of 3398 attendees of a gender identity clinic found that only sixteen (0.47%) of the participants experienced transition-related regret. Of these, even fewer went on to actually detransition and become detransitioners. Mind you, this is a gender clinic, where detransitioners often frequent after making the decision to detransition to get access to resources, hormones, etc. if they already had certain surgeries or otherwise.
In the US, a survey of nearly 28,000 people found that only 8% of respondents reported some kind of detransition. Of this 8%, 62% percent only did so
temporarily due to societal, financial, or family pressures. Feel free to read the entire 300-page report if you don't believe their methodologies.
And lastly for now,
another study of transgender teens found that only 1.9% of young people on puberty blockers did not want to continue with the medical transition.
Actually...
Another for good measure.
So... Yes. Clearly, there's some validity to people deciding they are trans. I'm sorry that it's impossible for you to comprehend the idea that people's intrinsic understanding of their own gender and sexuality is different than your experience with tattoos.