It includes 13 year olds because puberty blockers are included. No one is giving estrogen to children. If a child experiences gender dysphoria, their parents can have them work with a psychiatrist and their doctor to make sure they delay puberty so the child can keep growing and decide if they want to transition when they approach adulthood.
Everything else you’ve said is bullshit. Your ignorance is not a free pass to make up facts and spread misinformation.
Research shows that a lot of gender dysphoria is the result of puberty and medicalizing treatment of it creates a pipeline to further transition including surgeries, while if not treated, the dysphoria often desists after puberty.
This right here, this is evil. If someone took you at your word here, they may choose to ignore or punish their child if they were experiencing gender dysphoria. I know you have no sources from any respected institution, and the medical community en masse rebuke this line of thinking.
Edit: Both of the books the original commenter added to try and support their claims are books that posit TERF views that sex is biological and gender either doesn’t exist or is equally biological and cannot change. They dehumanize trans folks and their struggles. They are not medical studies or journals supporting their claims.