Hmm I've read something else on that...
From: The Anomalist
No, Your Zodiac Sign Hasn't Changed
An article in the Minneapolis Star Tribune
stating that our understanding of the zodiac was off by about a month--so people have been identifying themselves with the wrong sign--has had astrology watchers in a panic. On top of that the article claimed there was a 13th and neglected sign called Ophiuchus. But fear not, nothing has changed. There has always been two zodiacs apparently--a tropical zodiac, which is fixed to the seasons and which Western astrology adheres to, and the sidereal zodiac, which is fixed to the constellations and is followed more in the East, and that's the type of zodiac being referred to in the newspaper's article. So rest assured, if you're a Virgo, you're still a Virgo.