This kind of what happens when you mention a (tentative) release date. Even if you said it's just a guess, some people would go ahead and wait for the date as if it WILL be the time of release. And the greater the expectation, the bigger the disappointment.
Personally, though, this is no big deal to me. As someone who's familiar with public betas, though, I see little difference between releasing it early and releasing it late. While it would save you the feedbacks about the huge number of bugs in the form of complaints, you'll still instead deal just as much with the complaints of people needing to wait for too long.