I have many memories of the 3 years from the time I joined to the time I left the club.
I have many memories of the 3 years of my joining to leaving the club.
「入部」→「To join a club」
「引退」→「To leave」
「引退」を直訳すると「To retire」になりますが、この場合には「Leave」といったほうがふさわしいと思います。
「3年間」→「3 years」
「たくさん」→「MAny」
「思い出」→「Memories」
「ある」→「Have」
まとめて言いますと、
「I have many memories of the 3 years from the time I joined to the time I left the club.」
「I have many memories of the 3 years of my joining to leaving the club.」
と表現します。
どちらでも使えます。
Since I joined this club, till leaving, I have so many memories from these 3 years.
I have made so many memories in the 3 years I’ve been a part of this club.
部活 - club activity, club
Clubだけで良いです
入部 - join the club
入部した - joined the club
引退 - “retire” , retire from the club, leave the club
I joined the basketball club
I left the soccer team
I joined in April, and left in May
〜〜から 〜〜まで - from 〜〜 until 〜〜
〜〜年間 - Years
3年間 - 3 years, for 3 years
たくさん - many, a lot of
食べ物がたくさんある - there’s a lot of food
たくさんの思い出 - a lot of memories, many memories, lots of memories