Essays / Why do I want to study Aerospace engineering? - SOP required - what to write? [4]

I need to write an essay as to why I want to pursue aerospace engineering....the essay should be convincing and in about 2000 words...I also have to convince my dad with the same essay....the only thing is I don't know how and when to start because I don't have a clue about the subject...I have always been passionate about the subject and that's really it...