Is there a point in carrying on with the violin?

Ive been playing the violin for the past 6 years and have only worked my way up to a grade 4 standard of playing (i havent so far taken any exams and have skipped all the grading exams because i never really wanted to do them). Im currently in year 11 and am wondering whether or not its worth making my parents pay for another year worth of lessons eventhough the whole violin playing isnt going very well. I was planning on taking grade 4 in november but due to my teacher missing the deadline for the enteries i was not able to do so, which im very dissappointed and annoyed about. Im not sure whether or not i want to carry on with the violin but i feel like itll be such a waste to just simply drop it after my parents paying for 6 years worth of music lessons, which arent exactly cheap. I was wondering whether or not ill be able to just push myself through another year and do grade 6 June 2017 so i can have some exrta UCAS points but im not sure whether or not thats achievableand worth it keeping in mind that im currently only on grade 4. And obviously ill need to take a grade 5 theory exam before i do my grade 6 as the ABRSM examboard requires this. Is it possilbe to jump from grade 4 onto grade 6 in just over a year?
I just wanted to know what some people looking in from the outside think about this, and if there are any other ways to solve this problem?

PS my parents dont mind paying for me to carry on but it makes my feel so incredibly horrible knowing theyve paid so much and ive basically achieved nothing and i dont want them to carry on paying if im not going to move forwards with this