Parents are naturally protective. We can't fault them for that. Though I do believe we all, particularly our younger selves, know what will make us happy.
I want to see you be happy and that will encompass many things, particularly in a career. You say you see your self as an "idol". Do you mean trying out for American Idol or is that the measure of success you see for yourself as an entertainer? If it will be your measurement for deciding your level of success as an entertainer, it could be quite the challenge.
Someone who achieves that level of success makes a lot of money, after a while, and seems to have a great life but, they employee and support possibly hundreds of people. Honestly ask your folks, your teachers, your relatives, even people in your neighborhood who own their own business, "What does it feel like to provide for/support the number of people that you take care of from working for a living?" Ask them how many family members or employees they have to support. Ask them to be honest with you. Do they stay up nights thinking about how they can do a better job of supporting people? What's the best part of them taking care of the people they employee? What isn't so much fun about it?
I know quite a few professional musicians. Most of them truly love their art and their profession. Many of them work for big-time entertainers and one is even married to someone who was once "very big time". Still they are happy people, raising families and working hard to support their loved ones.
Your "later in life" dream seems to be something interesting to think about in the short term. Every musician/singer/performer starts out playing live. It's not always easy to find someplace to play. If you wish to run a cafe, why wouldn't you have people performing there live while you're open? Bruce Springsteen used to play at a cafe not far from me and it isn't any bigger than someone's living room! You don't even need both hands and feet to count the number of tables they have inside. There's nothing that says you can't run a successful cafe and sing there too, and sing other places too. If you get your cafe running right and have someone who can manage things when you can't be there - like your parents ;) - why can't you go out and build a musical career of your own, knowing your business will be there to support you while you're out paying your dues as a performer? You'll have regular revenue coming in. You'll always have someplace where you can perform anytime you want. You'll have the flexibility to do multiple things. And, you just may be able to help others with the same dream along the way.
There are many, many ways to get where you want to go, and still keep your folks from worrying. Read all you can about the business side of the business. That's VERY IMPORTANT.
This is one of the best books on the subject: Donald Passman's All you need to know about the music business.
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Good luck to you and feel free to ask all the questions you'd like. I'm happy to help you out.