请英文达人帮我纠正这篇我自己写的文章里文法和句型,

请英文达人帮我纠正这篇我自己写的文章里文法和句型,
If you could change your life,what would you want to do?And if you could achieve this goal,how would your life change?
I wouldn't want to go back into the past (mainly because I wouldn't want to relive that again) but I could change anything I would be my lack of confidence. I didn't have any confidence in myself. For example,When I read passages or answer questions in class,I am so nervous that I can't say a full sentence.After class,I speak fluently,but whenever teachers call me,I feel afraid.  The reason why I failed was that I lacked confidence.So I think that's what I would change.I want to be full of confidence any time.My life would be perfect if I had full of confidence.I think,maybe I can go to a great college.There can be no achievement without diligence and self-confidence.Of course,I like Soochow University now.