The thought of writing a book can be a scary one. Especially if it is your first time. From my experience as an author when I write I just don't think of my writing as a book.
I just write for the fun of it and just spilling my thoughts out on paper. I find it very refreshing to the soul. I even feel relaxed afterward. Try it. It works!
And if you get in the habit of doing that for a while, in no time you'll have a couple hundred pages of manuscript ready for editing. It helps to not think about it as a book.
That way you won't worry about grammatical errors as you write. That can get anyone discouraged from writing if the focus is on grammar during your first draft.
In case you need more help click here. That's how we take the Angst out of writing.