It’s insane that your parents test your blood for estrogen, that feels abusive and like something that should be illegal.
its a part of the blood test that i do for vitamin d regularly so i dont get a severe deficiency. T and E were both tested last time on request of my parents to know if maybe something was wrong with my hormone levels to cause my transness. turned out to be false of course. no idea if it will be tested again but i consider it a 50/50 chance.
EDIT: I’m not a lawyer, but searching around I found that at your age you can probably legally reject the blood test, see: https://en.wikipedia.org/wiki/Mature_minor_doctrine
this is only a thing in the US and i am in germany also it would be super suspicious to my parents
US-centrism again. It costs nothing for my family here. :P