In the long run, does money real matter? Most people today think you have to have a certain figure salary to be successful or whatever, but most of us get by happily with what pays the bills. In the long run, money isn't going to matter, because we're all going to die anyways and we can't take it with us. Sure, we want to be able to leave a legacy for our kids and grandkids but would it be better to leave them with a legacy of you having a happy life, doing what you love, and setting that example for them?
It absolutely, positively DOES matter. Most people I know do not get along happily by living paycheck to paycheck. If they are in that situation, they are stressed out, uncomfortable and always struggling and counting on that next paycheck.
It's not about leaving money for children, it's about having enough money to pay all the bills, get the things you want, save some money, and be comfortable.
It's easy to say "do what you love", but as SR said, it isn't always realistic. Work isn't about having a party everyday, it's about doing a good job and being useful. Yes, pick a job that doesn't make you miserable, but honestly, if jobs were so much fun, there would be people clamoring to do the same thing free.
That's not to say I wouldn't encourage the OP to follow her passions, but OP, if you want to be a writer, there's nothing stopping you from writing now. Go to college, write, and maybe you will be able to start earning while in college.
I have no idea what you should choose as a degree however. Most people do change degrees at least once, so don't feel bad about that. As you start college, you may discover you are very interested in a certain topic. College is a learning experience, and you will learn what interests you the most.
Another thing to keep in mind - many people have jobs now that have nothing to do with the degree they have.