…you’ll never get close.
I think this is true regardless of where you’re headed. It’s not enough to say “I want to be a musician” or even “I want to be a vocal performance major.” That’s nowhere near precise enough of a direction to aim. Some vocal performance majors are going to be high school voice teachers, others are going to sing at the Met, others are going to audition for the Met, never get an opera gig, and find a gig outside music.
Similarly, my vision for my ensembles has to be crystal clear: I need to know what I want my students to leave being able to do. If the vision is even a little bit nebulous, I will be frustrated, the students won’t perform as well, and the learning will be diminished.
When you start off on a journey, you probably don’t know enough to precisely define your vision. But as you take your first few steps, it’s important to continuously hone and shape your vision until it’s precise, concrete, and achievable.