No possible way it would fall to ZERO, I don't think. There MIGHT end up being two competing chains, but you'd have coins on both chains and could then decide whether you want to add to or remove your position in one of those coins after that date.

I will note, I've 'diversified' into a couple others, just in case a fork causes people to panic, especially if one of the teams decides to take their ball and go home rather than continue working to make their fork the more popular one.