I want to be a theatre performer, only 13?

i live in cardiff, wales then country by england it's like england. any way we have loads of theaters etc... and i really, i honestly mean it i want to be on the stage acting and singing my heart out. all my other friends say they want to be models be in movies and so on, and im the only one who said theatre, they smiled and they said i'd be really good. i go to drama and singing class, and im being Elphaba from wicked soon, and they say i could be in the theatre, but what tips could you just give me to improve my skills and have a better choice. thank you xoxox