Note that daylight is NOT exactly 12 hours!
If anything we get closer to 12 hours 3 days later.
There is a reason for that. It is our latitude above the equator.
If we were closer to the equator it would have been closer to 12 hours.
See this explanation in Time-and-Date.
My equinox diagram.
Click to ENLARGE, study and admire.
Another ‘Time-and-Date‘ diagram annotated by I.
Related Posts: Search on ‘equinox’ for lots of other posts with tons of pictures & diagrams.