How would you say: "But only X years ago, in month Z of Year Y ..." in Taiwan
In Chinese, we use 'Y-M-D' format for stating date.


  "But only two years ago" - "祗不過兩年前"


~


  "in September 2015" - "在二零一五年九月" (In Chinese, we state year before month)


or

"在 2015 年 的九月" - "in September of 2015 

Emphasize the month if it is an important information. For example, September is the end of summer holiday