I have an easy solution to this matter of living and dying, Saz:
Remember that although it could be tomorrow, or 90 years from now, when you're a vibrant, engaging old lady, you are ALIVE!
And for this reason, you have things to contribute to the world.
You have everything to give, and a whole world as your audience, of you wish it, so make the most of that life that you fear will end eventually.
You see, everything has its time on this earth, and everything has its time to move onto the next world, wherever, and whatever that may be.
It's about fighting the good fight, and doing what you love in the meantime. Sometimes, it's not so fun, and I know it's really, really hard to smile some days, but without the bad bits, we couldn't truly appreciate just how good the good ones really are.
Don't worry about when death comes, worry only about this question: 'have i done all that i can in this day?'
Keep smiling Saz, keep writing, keep being just you, because just you is enough, just you is perfect.