One thing that Keffals and Troons in general don't understand is that there's a reason why age of majority laws exist for a reason because people that are below an established age of majority don't have the maturity to make life changing decisions because they don't really understand how these kinds of decisions can affect them later on.
If you want to troon out by age 18 then fine, in most developed countries age 18 is seen as being a legal adult where they can now make the choices they want to make without permission from their parents. Whatever you do as an adult is up to you.
But when it comes to minors, there's a reason why parents have to allow permission and have the power to say "No" before their child can engage in anything and why kids are also restricted from engaging in some activates. You cannot get a tattoo on your body until you're 18, you cannot be legally allowed to drive until you reach age 16 or 18 depending on the country you live in, you cannot legally buy porn until age 18, you cannot serve in the military to legally kill people overseas until you turn 18, you cannot open a credit card account by yourself until you turn 18, you cannot buy alcohol or tobacco products until you reach the legal age, the list goes on.
Whatever you do as an adult that's on you but don't try to make minors make big life changing decisions based on your skewed ideology. People regret getting their first tattoo and get it removed afterwards but hey they're adults so getting a tattoo is a decision they made as a mature adult and getting it removed is also their decision if they regret it, if you troon out a kid where you mess up their puberty cycle and they regret transitioning that is going to have a lot of long term damages for the rest of their lives anyway.