don't go into music thinking only 'piano , piano.' think in very broad strokes, imo. that way - you can do many things with a music career. even take a business class or two. some computer classes. maybe these would be part of your electives - but enjoy them and do well in them, too!
it is so neat to meet an all around musician. usually they are conductors. they understand how to play piano well, but didn't necessarily focus on it to the extent that some do. but, the money is there in larger quantities faster, i think. take a chorale. you've got fifty or more students automatically. or, a community college symphony. those are paid students. i don't know why - but it is always harder (and keeps getting harder) to find single piano students that are truly freshman level at piano and students that teachers want to teach. so if you have a limited number of students for piano at first - you can also do other things!
imo, you will lose time and money on refurbishing pianos. people don't buy them that often. you can spend countless hours on that - as with practicing - and enjoy the time immensely - but not get paid enough. you need a job to really tide you through the bills that start coming at you. and, a company that will pay your health insurance and take out the typical stuff you have to keep track of when you are self-employed. self-employment isn't worth the time anymore - basically. look at the the price of gas alone! car repairs. the list goes on.
a friend of mine had a shop in california (actually a real shop behind her store front and piano studio). she and her husband sold instruments, repaired, she taught lessons, and also played for karaoke nights at certain places for fun. between all of that - they eeked by - but didn't have a lot of extra spending money. the thing is - when you really love something - you just don't care so much. but - she said the work was hard and sometimes overwhelming. a lot of music stores go broke. even big ones. it would all come back on you. much better, imo, to work for a college or a school and just put in the hours and be able to come home, eat dinner, and practice - and basic things like that.
also, i think the idea is that if you do something well, you can teach it later. say, with composition, music history, piano lessons, master classes, specialties in music.