@xKatieJane Hi there. Thanks for your question.
Screenwriting CAN be a lot of fun... when it's fun. But it can also be incredibly challenging, like any kind of creative writing. (When it comes down to it, it's just you vs. the blank page... and there's only one way to make sure the blank page doesn't win.)
As for pursuing it as a career, it's not the sanest way to make a living. You can spend months, or even years, working on a story you love... with no guarantee it'll ever see the light of day. On the other hand, when something DOES get made it's an incredible experience, and worth all of the time and effort.
When I was in high school, dreaming of going to college to study film, I came across many professionals who all said essentially the same thing: "Only go into screenwriting if you feel like you have no choice; if you absolutely have to." That's definitely how I felt back then, and it's how I still feel.
If you love movies more than anything, and love telling stories, AND if you have a lot of patience and faith... then you might want to give it a try!