Why is the constellation of the planetarium a month later than usual?

Hello, AAS, Astronomical Society of Middle School Affiliated to Fujian Normal University, will answer your questions.

Due to precession, the vernal equinox moves 30 degrees to the west every 2 166, which means it moves by a constellation. On March 2 1 day, more than 2000 years ago, the sun entered Aries Palace, and now it enters Pisces Palace, so it will be one month late.

I don't know astrology. I hope it helps.