No really, this is part of determining your own commitment to a a very solitary and time-consuming project.
If it's cause you think it's a way to fortune, it's kind of not. Book world is like entertainment world--many hard-working, equally-talented people toiling in obscurity and then someone hits it big. That lucky someone will try and tell the story of believing in your dreams, but it happens not that often and we don't want to rain on your parade, but the JK Rowlings are few and far between.
If you think it's a way to fame, see above.
If you have something to teach or a story to tell, test-run it by your inner circle and see the reactions.
Writing a book is hard work, and it isn't going to stop with turning in the manuscript. You'll need to work on editing, proofreading, coordinating with a designer, and then with the publicity and ongoing efforts to sell books and parlay your author status into expert status in your field. We happen to think that is the ultimate payoff for writing a book--that you will then be called upon by media and others in your field of interest for your opinion, comments, and expertise. Your book will be your stepping stone.