Leap year recurs every four years, and in that year February have 29 days. But according Chinese Traditional Calendar, Every 19-years have seven-leap month. Unfortunately, Mr.Baker has born in February 30. When he twenty-third, just celebrate ninety my day.

請問有英文好的朋友能解釋一下上文關於23歲和90歲之間的關係嗎?
不勝感激~~