Here's the answer:
“初めてじゃないです”
(hajimete janai desu)
Watch a real native speaker say it:
Here's how it sounds in a textbook:
You could also say:
- 初めてじゃない
- 私は初めてじゃないです
Fun fact: the hundreds of thousands of people learning Japanese with Memrise get this phrase correct 90.54% of the time!
