i need a personal answer from someone who is experienced in writing books....?

[Kiera]

I'm a beginner writer, I graduated high school with A's and B's in my English classes. I've also made B's in middle school with English. i love literature and but it was tough for me in school in general caise i have ADHD and have a hard time focusing on one thing i jump around A lot . would it be wise to dabble a little by practice writing or retelling stories i love as i would have wanted them to end or happen to certain character (not to be published of course) but just for fun and be able to break it down easily.? and be able to get creative with things.? whats the perfect method to writing a story or a book.?... I'm 19 and just graduated high school so all I'm left with is the ever popular umbrella method from the writing FCAT lol i saw the snowflake method but it seemed to complex for me being a beginner.