There would be a fundamental and extremely well established principle of content consumption that would be violated. Not just the web, but for centuries written content has always been written from the top of the page. Sometimes left to right, sometimes right to left and sometimes vertically, but always starting at the top.
Such a website would be incosistent with virtually all other web pages produced and as such would be akin to swapping brake and accelerate pedals although perhaps not with as devastating results.
The f-shaped eye tracking pattern supports this:
I would not advise it. I think your analytics would show a high bounce rate and any observed users would often show confusion because they wouldn't think to scroll up.