I don't care what one does with their own body
And yet... you do.
don't use taxpayer money to change your gender
You can't dictate what taxes go to, but in this case, as far as I know tax money does NOT go to people to change genders. In order to get GRS, you pay out of pocket because it's considered cosmetic.
and no blockers or cosmetic surgery until they are over 18 when it is truly their own decision.
Blockers at 18 defeats the purpose of blockers. The reason they're ON blockers is to stop the process normally gone through at puberty so they can make an informed decision and then at 18 (or sooner if the patient decides they don't need blockers) get GRS. That's been brought up repeatedly but the same lie keeps getting spread around.
But you should agree that there is only 2 biological genders
No I shouldn't agree because no there isn't. Science just isn't proving that.