Thanks so much everyone for all of your insightful responses.
I know that it is a lot easier to write about real life events that I have encountered with, but the one big thing that I could write about is very painful for me and I do not want to "re-live" it through writing a novel. As such, I am left with no choice but to write a fictional book.
I don't really care about royalties or anything like that since I am doing this not for the money, but rather, for self-fulfillment. I suppose the decision with respect to the type of publishing is not really relevant at the moment for myself. But big thanks for providing all of this useful information.
MyBirdIsEvil - I know that sometimes it's better to just start writing... but I feel as though I cannot simply write before I know the exact outline/characters. To me, writing is very similar to building a house: you have to have all of the engineering/architecture/plans done first and only then you can start building it. If you just start building, the end result may not be all that glamorous because proper calculations were not done. But then again, I'm sure that some unconventional writers also write without first having the "skeleton" down.
Anyway, writing a book is just something I wanted to do recreationally. My full time job is very very different....
Thanks once again for all of your advice! You guys are great!