Nah, it always starts on the equinox (though if it were up to me equinoxes and solstices would be in the middle of seasons). Just that date changes a bit each year because it deals with the movement of the planet through space rather than the calendar.
Also, fun fact, apparently the equinox is when the sun is directly over the equator rather than when day and night are equal, which usually happens a few days later in fall and a few days before in spring.
Always a bittersweet time up North. It's the prettiest time of year, but the days just get progressively darker, and we woke up to snow on the hills this morning.