I think you're wasting time that could be translated to "more good books." To each their own, though.
I'm just of the opinion that any organized plan to read "only great books" (regardless of reason or age) is an exercise in futility. But I don't think it will harm you in any way, and I sincerely wish you luck with your list. And like others have mentioned ... allow for some flexibility. You don't want to feel guilty for breaking your regimen for a new release.