I see you are in Louisiana. You have a lot of great opportunities to make a living as musician there. When I lived there, I did, and my wife who is from New Orleans, did, and her son, who is still there, does. My family did not want me to be a professional musician, and, even when I went to Loyola in New Orleans to further my music education, I still got that "when are you going to get a job?" question, even though I was playing almost every night and going to school. It can be done. You should look at music ed at Loyola New Orleans, or LSU, even Nichols U in Thibodaux, if you're down in the bayou country. You could go to school and be a band director, or music therapist, or film composer, or a great bass player-but you need to get exposed to the wide variety of things that can be done under the umbrella of "musician".
That said, here's my two cents. I don't know where you live in the state, but Lousiaina has a rich musical heritage, and you should build on that. The Cajun and Zydeco music scene is very active and needed world wide. Are you Cajun French? Can you speak the Cajun dialect? Can you sing? If you can do both, and play bass, you have a jobs waiting for you. The New Orleans style R&B and jazz are the foundation to a lot of music. Don't forget - New Orleans is the birthplace of jazz. You are in a great location for a musician. Look at the long list of music greats from the state, start with Tab Benoit, go back into his Cajun heritage. Check out the Meters, Allen Toussaint, Lee Dorsey, Earl King, Band like Little Queenie and the Percolators. New Orleans bass players like George Porter,
James Singleton.
Your SX bass is fine - it's probably of better build quality than an original P bass, so don't worry about that right now, but concentrate on getting better and finding a mentor who is out playing. You can get a new tuner from Rondo, if that is what is needed. And in a few months time, you can move to a better bass. SX's are good basses for the money. What I am saying is you an do with what you have for the time being, but you need to focus on other things that are more important to your development as a musician. As far as your parents go, don't bug them about it. Your task is to prove to them that there is a need for what you want to do, and you will do what it takes to get where you want to be. You have to prove yourself. You say you are 17, and that is the age where you are testing your wings, and slowly pulling away from your parents and trying to become your own person. Your folks may not like that - it's normal- they may not want to admit that you are only a few years away from adulthood, but it's called growing up. Time to set your own course. Be kind to them but do not anyone stop you from being what you want to be. It is up to you to put forth the effort to succeed.