How does someone know, at the age of, lets say 26, that they want to be with someone for the rest of their life?

Or at the age of 18, decide that you want to major in biology at school because you want to end up in med school and become a doctor and do that as their lifelong career choice? How do you know that that's what you really want to do? What if you get all the way to med school and realize that you don't really want to be a doctor? What then?

I guess it's just really hard for me to believe that people can choose one thing that will ultimately be with them for the rest of their lives. What if they change their mind? Fall out of love?

I hate the fact that I grew up moving all the time. It was one of those things that would allow me to start over every six months, or every other year. I feel like it wasn't a healthy way to grow up cause that's how I feel like life should be. If you're doing something, and it's not that fun/exciting anymore...move on. Do something different. How's that suppose to work in relationships?!

It's frustrating. Damn you commitment issues!!!