Ok, kiddo, sometimes people in East Asia count their age a little bit differently than we do here in the United States. They use a system called East Asian age reckoning.
In this system, you are considered to be one year old the day you are born. So, even though you just came into the world and you're not really able to do much yet, you're already one year old!
Then, on every New Year's Day, everyone's age goes up by one year. So, even if your birthday isn't until later in the year, you'll still be considered to be a year older on January 1st.
This can be a little confusing at first, since it means that someone born in late December might be considered to be two years old just a few days after being born! But people in East Asia have been using this system for thousands of years, so they're used to it.
And that's the basics of East Asian age reckoning. Now, go have fun playing with your toys!