Do they really know what's best for you?

I was deciding what classes I will be taking next year and I think I finally figured them out. That got me thinking about what the guidance counselor said to me last year. "Are you sure you don't want to take this instead?". Yes I'm sure. Why do they try and change your mind anyway? Just when you think you are positive about taking something, they find a way to make you confused again. She almost convinced me to take an easier class than what I took. I guess she thought I couldn't handle it, but I ended up taking the class that I originally wanted. I passed that class with a high B. Does it look like I handled it okay? I think so. It turns out that they did the same with a lot of other students. They made them change their mind and the students ended up regretting it later. Do counselors really know what's best for you?
        The same thing happened to me yesterday. We were in the car and my mom and me got into an argument. I strongly disagreed with what she had said, and I told her that she was wrong. I know she was trying to help and figure out what's best for me but you just don't say those types of things. A lot of times other people think they know you and so they try to make your life easier. There is also a line that you do not cross, and a time when you should make your own decisions.