Does Chinese zodiac start in February?

The animal is a branch of the year

Each zodiac animal stands for one of the twelve earthly branches: Rat for the first, Ox for the second, Tiger for the third, and so on. In saju the year branch sits in the year pillar, and that pillar rolls over to a new year only after Ipchun.

Two different dates

Lunar New Year follows the lunar calendar, so it moves between late January and mid February. Ipchun is a solar term and stays close to February 4 every year. In some years Lunar New Year comes first and in others Ipchun does.

When Lunar New Year comes first, anyone born in between has already started the new animal by the popular rule but still belongs to the previous one by the saju rule.

Which one to use

For a saju reading, use Ipchun. Crossfate sets the year pillar that way. If your birthday is in early February and the animal is unclear, enter the date and check your year pillar.