Yes, you read that correctly. In Thailand it is 2558 not 2015. I am the only teacher who writes 2015 on the homework board.
The Thai years are based on the year that Buddha died which was 543 years before Christ. The Thais celebrate three New Years: the tradition day of January 1st, the Chinese New Year in February, and Songkran in April which was the traditional New Year celebration until the muffle of the 1900s when it was changed. Songkran is still a big celebration in Thailand and is basically a humongous water fight.