Life really all comes down to luck. If you were unlucky, you might've ended up part of the 3.9% of children that never grew past the age of 5. If you're extremely unlucky on any single day in your life, you might just randomly die. Maybe a sudden gas leak. Maybe a random accident. Maybe a random health condition. It could be anything really.
Never forget that just still existing already means that you've been luckier than some others.