Good work; you successfully managed to time the market. I'm sure there were many, many others who didn't make out so well.

Now redo the calculation a bunch of times to account for all the other possible times you could have both opened and closed that short position, and see how many other times you would have turned a profit. Probably not in many of them.

You got lucky. Contrary to some popular belief, lucky timing is not a generally-applicable investing strategy.