I laughed when I read this, partly because it is entirely correct, and partly because exactly this happened with my younger daughter. She could have almost written the original post 7 or 8 years ago.
I know one single person who knew that they wanted to do as a junior in high school, and stuck with it through university, and stuck with it through their career. Other that this one person, there appears to be two types of high school juniors: Ones who do not know what they want to do, and ones who do know but who are going to change their mind.
So my younger daughter in high school had no idea what she wanted to do with her life. As a junior in high school she did express concern to me that her friends knew what they wanted to do, but she had no idea. I pointed out that her friends might know what they want to do, but in six months or a year they will change their mind, and we all work it out over time. This daughter applied to universities not knowing what she wanted to do, but applied as a languages major. After one year she switched to be a biology major. However, this required that she take four lab courses at the same time. The obvious thought is: Is this crazy? Four lab courses at once??? She discovered that she loves lab work and is very good at it. She went on to take as many lab courses as she possibly could for the rest of university, graduated, and right now as I type this she is in a biotech lab doing cancer research.
She did not figure this out until she was part way through university. That is probably earlier than most people figure it out.
@mara.k you too will figure this out over time. To me it sounds like you are doing very well, and are thinking about issues that very intelligent and thoughtful students will think about from time to time.