There are two kinds of writers who are doomed to fail:
1) The person who talks about how he or she dreams of writing a novel someday.
2) The person who wants to write, but has a list of reasons/excuses why he or she can't.
If you see yourself--even remotely--in either of these categories, you are not a writer. You're a talker.
Of course, it's a lot easier to talk about doing something than to do it. And it's easier still to blame the world, the people around you, your life, your lack of time, or a million other things for why you aren't doing the things you want to do with your life.
It's much more difficult, but infinitely more rewarding, to take ownership of your time and your life and dedicate a portion of it to meaningful creative pursuits.
Don't waste any more time talking about writing or making excuses for why you're not writing. Just shut up and write.
PS: You can substitute any creative endeavor in place of the word "writing" above--songwriting, painting, photography, running, traveling, etc. The point is, do you intend to talk about these things or do you intend to do them? Better to know this sooner rather than later.