Talk:Sakuragaoka High School Light Music Club/@comment-111369-20150721055244/@comment-25308539-20150721080926

The key word in your question is known. We don't know any generation before Sawako's, so we can assume they're the first. Next, there's about a 6 year gap in age between Sawako and the third generation. So when Sawako starts univeristy, the third generation has just started middle school, and the second generation starts high school. When Yui and friends start high school, we know that the outgoing year (the 2nd gen) had the last members of the LMC.