That's like saying Huckleberry Finn doesn't exist. Just because it's made-up doesn't mean it doesn't exist. It exists as a concept which billions of people understand.
Turns out you can make up any arbitrary distinctions and they just start existing. The question is if they severe any useful purpose.
I can make zodiac 2.0 exist by adding shoe size to distinguish between regular aquarius and aquarius without platypus (above EU 42 is with). So now the Zodiac 2.0 exists with the same predictive power as 1.0.
Considering how the universe is full of stuff circling around stuff circling around stuff circling around... the zodiac signs have moved over the last couple of millenias.
Actually they do. The zodiac sign constellation of a day correspond to the constellation over which the sun while be at noon. So you do have a zodiac sign constellation associated to your day of bird.
But depending on how your culture group stars in constellations you might be from a different zodiac.
If you want to follow a classical westerner map of the sky, they will be 13 of them.
Also, note that the zodiac signs won't cut the year in equal parts. Some constellations are just bigger than other and the sun path across the sky changes more or less quickly from a day to another depending on the time of the year.
Zodiac signs are literally constellations... Which are quite real.
Astrology is also real, in the fact that it's a uselessly real thing. Women love it though. Same with tarot. All you do is make plausible sounding shit up and then they placebo themselves into happiness or nocebo into a sour mood.
The actual signs exist (get yourself a planisphere or a stargazing app, find some dark skies, and discover them for yourself!), it's just all the magic personality nonsense associated with them is bullshit.