When was/will Polaris's declination be maximised? In what year was/will Polaris be closest to the north celestial pole.
Soon after 2100:
In 2018 Polaris was 0.66° away from the pole of rotation (1.4 times the Moon disc) and so revolves around the pole in a small circle 1.3° in diameter. It will be closest to the pole (about 0.45 degree) soon after the year 2100. (text from Wikipedia)
Nutation (a wobble in the precession motion) means that it will actually approach and receed slightly from the Pole several times in 2100, in the model used by Stellarium. In that model it is never closer than on March 26 2100.