Should I join or should I just say no?

Ever since 10th grade ive been thinking about the military... I asked people so many questions and always get different answers.. I have decided if i do it i'm gonna do the airforce reserves.. I just don't know what i want to do in the airforce reserves yet..I want to do it to show people im not who they think I am that I am strong I want to show myself I'm strong n I want to fight and defend my country.. I got a book to study for th ASVABS and when i started looking over it i realized i didnt get half the ****..some of the math and machanics n electric parts n it gives me a head act so I'm starting to rethink it..I really want help with college but i don't want th emilitary to own me and make my depression worse bc i can't be around my family friends n fiance bc they all mean alot of to me....I'm just really scared...I was just wondering if I should do it or not..bc idk if im wanting to do it for the wrong reasons or not or if joining the army is even worth it?...plz help...