I'm glad I could ... because we haven't had one together for such a long time.
It's nice that we could ... since we haven't had one for a while.
ーI'm glad I could take a lesson with you today because we haven't had one together for such a long time.
「長い間なかったから、今日あなたとレッスンができて嬉しいです。」＝「久しぶりにあなたのレッスンを受けれて良かったです。」
I'm glad I could ... because we haven't had one together for such a long time. で「久しぶりにできてよかった」と言えます。
ーIt's nice that we could have a class together today since we haven't had one for a while.
「しばらくなかったから、今日あなたとレッスンができて良かったです。」＝「久しぶりにあなたのレッスンを受けれて良かったです。」
It's nice that we could ... since we haven't had one for a while. で「久しぶりにできてよかった」と言えます。
ご参考まで！
カナダ 
