It is quite competitive that there are only five instructors available for reservation.
The competition is pretty fierce considering that only five instructors are available for the lesson reservation.
ご質問ありがとうございます。
① "It is quite competitive that"＝「～はかなり競争率が高い」
"there are only five instructors available for reservation."＝「たった5人しか予約できる講師がいないということは。」
② "The competition is pretty fierce"＝「競争はかなり厳しい」
"considering that only five instructors are available for the lesson reservation."＝「レッスン予約に5人の講師しかいないということを考えると。」
ご参考に。
アメリカ合衆国 
