So blades I was thinking I'm gonna start writing a book in my spare time (which I have alot of) anyways I have a basic outline of it but realistically it would only be about half of the story, my question was should I start now and just go with the flow of it all or should I plan out the whole story first the write it?
The only way to write, is to write. As you do, more ideals will connect and spring onto the page, sometimes in ways that surprise even you. I wish you the best in your endevour!
I think you should plan it first to make sure you have all the connections. If you write it and you suddenly realize there should be a connection or something else, you will have to find a way to fit that into your already written parts, which would be harder and it wouldn't resonate as well through the rest of the book.
Some planning is good but really it depends on who you are, everyone is different and what works for someone else may not work for you, so do what works for you, mate. For me I get nothing done if I try to plan it out. Going with the flow is my way of writing and I love it. Going back and making changes or rewriting pages will happen no matter what you do, no matter how successful an author you are.