A general guideline I was taught since a very early age goes about those lines: it is important to remember to put 100% of your efforts, never giving up but most importantly have the wisdom to know when to be patient and when to press hard. Anyone can write a book just the same way anyone can learn how to make music or drive a car. The important part is how much will you benefit from learning how to master that skill. The real answer is that you will get to know yourself. No matter what you learn, if it's new and if it's hard, the lessons will always stay with you.
Writing is not hard. I am not the best writer in the word and even if I am smart, I do know that I am not eloquent to ever become Stephen King. Still... I am writing a book because there is a message I believe will benefit people. I also believe that this message is going to provide much more value than the cost to purchase the book. Finally, I believe that the book will be a contribution to the human condition. For this reason, I have no excuse not to write a book... on the contrary, I now start believing I have the responsibility. This became my driving force.
The process of writing my first book has already taken one full year and it will probably be finalized within the next two months. When you surf the web searching for writing tips, every blog and writing expert is trying to sell you a magical program on how to write a book in 90 days and publish it. This to me signifies three things: First it is the irrefutable proof that my eloquence is not great and I do take more time than what an average writer would ever consider reasonable. Second it proves that objectives can always be achieved with the correct amount of time and effort. Finally it gives confirmation that the calling was truth because the book wrote itself through me. What I'm saying is that even if my writing speed is set to turtle mode, this book forced itself through my brain.
So I encourage you to take on writing... It will de-clog your brain and writing power. It will also force you to read so you start learning how to better communicate. And if its good, your book will be helping someone that needs it.