Yes - there's no such thing as 'too early'. Of course if you've been working for a while, you should certainly show what you've made so far.

If you consider the rather common case of a YC application where the founders (1) have been working on X, (2) get into YC, (3) eventually drop X, and (4) eventually find something else that goes better...you're essentially skipping to step (4). (Not that the analogy holds in every way, but it does for "should you apply" purposes.)