Life is not a race, people do things at different times. Just because other people are getting part time jobs now doesn't mean you should - everyone's circumstances are different.
Now lets look at Maslow's hierarchy of needs. Do you have enough food to eat? Do you have clothes to wear? Do you have a clean place to live and sleep? If you have all of those things then you are significantly luckier than a decent section of the world's population. Life doesn't suck.
Next, it sounds like you have 2 parents and they are willing to spend money on you. If they are kind people, who want the best for you, then that's a good deal better than some of your peers who are already working lots of hours so that they can start saving towards moving away from unpleasant, toxic or abusive parents. Life doesn't suck.
Next, it sounds like you are making really impressive progress with your piano, keep going. So what if you don't get grade 7 within the time? You aren't expected to go from this straight into composing music scores for films. Instead, you simply find a job that you won't hate and continue learning piano on the side, look for jobs in the music industry that you want to do and find out what you need to get there. It's much easier to be applying for jobs you want to do whilst you are in a job already (that isn't the dream but you don't mind doing it).
You're getting way too ahead of yourself, the future isn't linear - the job market doesn't operate in straight lines. Appreciate the things you do have, lots of others don't have them, life doesn't suck.