It doesn't end it just clocks around a new leading digit (from 12 to 13), it last did this in the 17th century and nothing happened.
Not speculation, our orbit around the galaxy is inclined - we must cross the plane twice in each rotation.
Apart from the complete lack of any mechanism to link these, the galactic orbit period is 220Myr and very regular.
Magnetic field reversals are not at all regular (and are probably chaotic) but occur at an interval of < 1Myr.
But lots of other species have and don't seem to have been over worried.