How to tell my mom that i wanna be actress?

I'm 14 years old, i already told her that, but i think she don't get it serious, my aunt and her were talking and my aunt said: ''oh if you want i can spend some time with her on RJ for making audition and this stuff, if she has talent..'' ( i'm brazilian) but i wanna go to USA, i wanna enter into some drama classes and put my heart into it , but my mother don't know that i dream so high , how tell her that i want it without sounding ridiculous ? i wanna prove to people that i can do it, i can like imitate,impersonate persons really easy and perfectly, my friends say that i have to be actress and singer, (they aren't lying)