I always wonder about the people who say they want to be writers, but they don't write particularly well. Maybe they like to write, but whatever they write isn't particularly interesting or profound or novel. Some don't even seem to have any particular intrinsic motivation to write, other than to vent their own feelings and complain about things. Even that gets old after a while. Before you go, what the heck, you hypocrite, keep in mind that I have no intentions on being a writer. I write for myself, and that's that.
Lots of people think they have good ideas. Nine out of ten people think they have good ideas. Most of them aren't really special. When I was in middle school, I thought that when I was older I should write a book about my life story, because it was so angsty. Now I look back on myself and want to laugh to death. My life isn't really interesting or even super-painful. It's so average. I have nothing to bring to the table.
If you really want to be a writer, start practicing. Stop thinking your diary entries are legitimate writing samples. Read the newspaper, read all the great classics. If you think As I Lay Dying and The Adventures of Huckleberry Finn and 1984 and Shakespeare are incomprehensible, stupid, and/or pointless, then you should find another path for your life. Look around you. Read everything. Form your own opinions and creative path. Write about that old person eating alone at McDonald's. Write about the sidewalk. Write about politics. Write about nothingness. Write a real story.
Writing about yourself won't really get you anywhere. You're going to need some real talent, and some people just don't have it in them. Try to objectively identify whether or not you have it. Nobody really wants to read things about your life, unless you do something historically relevant first. People want to read about things that are relevant in their own lives. That's why beauty blogging is such a huge industry. It's largely vapid and redundant, but everybody is on a quest for beauty. It's also why the news articles and soap operas and health articles are popular. It's also why sex sells. Write about something you are passionate about, and then connect it to everyone.