Support child’s dreams or create false hope?

My 11 year old daughter is convinced she is going to be a professional musician/ singer. She half heatedly plays the trombone. She never sings. Her uncle is a professional musician and she has seen and heard how much he has to practice and how difficult (feast or famine) the industry is. She won’t entertain any other option for her future, yet seems lukewarm on what she says her “passion” is (we have to beg her to practice her instrument. I know she’s only 11, and I don’t want to crush her, and part of me feels like if I don’t give her a reality check she will be crushed anyways. What would you do, more seasoned parents?