Im Writting A Story And Would Love Your Opinions!?

Okay So I Love Writing Stories But Its Been About A Year So Im A Little Nervous This Wont Turn Out As Well As My Others. Its About A High School Couple. Chelsea(Female Main Character) Has To Leave Because Her Sister Is Dieing But When She Returns She Finds Brandon(Male Main Character) In The hospital from a terrible accident. But The Worst Part Is He Hardly Remembers AnyThing! And Chelsea's Best Friend(Or So She Though) Made Brandon Believe She Was His GirlFriend!.... I Have The Plot But Now I Have NOO Idea How To Start It, Any IDeas :/