I think this is something a lot of people think about regardless of their age. I believe that it is 100% okay to change careers throughout your life, if you believe you are following your heart, interests and passions.
In college, I changed my major about three times! It was through taking classes and having internships that I realized which jobs I liked and what I didn't like. I started off wanting to be a zoologist and ended up graduating with a marketing degree! :)
Even outside of college, now as a working professional, I've changed my career. I started off in sales, and then 5 years later, knew it was time for me to follow a different passion (which is recruiting).
The point I'm trying to make is that I think its 100% okay to change careers, but I encourage you to give yourself the ability to find out what you like and don't like, whether its through first hand experience (internships, jobs), classes or through other research (like talking to others who have a job you might be interested in). Some people know what they want to do, and have their career their whole life, which is great! Others may try many different careers before they find something they truly love.
Best of luck to you!