I was born in1April 22, 996, when I was a Gemini. Why am I a Taurus now? Will it change in the future?

The constellation will not change. You said that you were born on April 22nd of the lunar calendar in 1996 and June 7th of the solar calendar in 1996. You can tell it's Gemini by checking it. The constellation after the solar calendar query in the year of your birth is your constellation, instead of converting it into the solar calendar every year according to your lunar birth date, so you may change the constellation several times, which is wrong.