When will I be able to see the 12th Planet?

The Zetas state that technically it is now visible to the human eye, though only an educated eye would see it. See:

ZetaTalk: Comet Visible

Just prior to the Pole Shift, The comet will be visible to the eye for approximately 7.3 weeks, certainly no less than 43 days, prior to the great gravitational and magnetic disruption we have described. From:

ZetaTalk: Time Frame