The geological record is unambiguous
Magnetic minerals locked into volcanic rocks and seafloor crust record repeated polarity changes. The last full reversal occurred roughly 780,000 years ago, but intervals between reversals have ranged from thousands to tens of millions of years.
The field really is changing
Measurements since the nineteenth century show a decline in average surface-field intensity and rapid movement of the magnetic poles. Those changes are real and are why navigation models such as the World Magnetic Model are periodically updated.
Why weakening does not equal imminent reversal
USGS notes that field intensity can vary substantially without a reversal. The present field is still strong compared with much of the recent geological record, and scientists cannot reliably predict when the next reversal will begin.
A reversal is not a doomsday switch
During reversals the field becomes weaker and more complex but does not vanish. Geological and fossil records do not show previous reversals causing mass extinctions or catastrophic climate shifts.
Research record
USGS — Are we about to have a magnetic reversal?Official · open sourceNOAA NCEI — Geomagnetism FAQsOfficial · open sourceNASA — Why magnetic-field variations are not causing climate changeNASA · open sourceIs Earth’s Magnetic Field About to Flip?
Direct answer: Almost certainly not in the immediate future. A future reversal is inevitable on geological timescales, but current weakening does not let scientists predict when it will happen.
Reversals are established Earth behaviour; imminent-doomsday claims are not. The main realistic issues are navigation and increased space-weather exposure during a weakened field.