Good luck! I've written two novels and about 100K words of the first draft of a third. You're right; it's difficult. But it's also one of most fulfilling and creatively satisfying projects a person can undertake. Enjoy the process and remember that decisions can be undone at a future date. Just enjoy writing that first draft and winding your story through the forest of your mind from point A to point B. Improvements can be dealt with during later drafts.