I know I'm trans and I have told some people. But I cant work up the courage to tell any adults in my life when they use the wrong pronouns. What can I say or do for them to understand on the right way I'd like to be addressed?

In a world that uses labels to identify people, it is super important that they are used correctly. There is no harm in simply correcting them, "Hey, I would actually like to go by he/him or she/her". Don't let your identity be defined for you; your pronouns are your pronouns and you have a right to ask for them to be used correctly. You can also remind them that gender is a construct and a spectrum and that your change in pronouns does not change who you are as a person, deep on the inside, but that you simply find more comfort in identifying with these labels.