It took a lot of time to get used to the curriculum at university since it's completely different to the one from high school.
カリキュラムはcurriculumと言います。
「大学のカリキュラムが高校までと違いすぎて慣れるのに時間がかかりました。」
"It took a lot of time to get used to the curriculum at university since it's completely different to the one from high school.”
時間がかかりました - took a lot of time
違いすぎて - very different, completely different
慣れる - get used to, adapt to
高校まで - up until (the end of) high school. 前の英語の文に「the one from high school」で書きましたが、「the one I had until the end of high school」でも使えます。そうしたら、「It took a lot of time to get used to the curriculum at university since it's completely different to the one I had until the end of high school」になります。
The university curriculum was so different from high school that it took me some time to get used to it.
こんにちは!
ご質問ありがとうございます。
先のアンカーさんが回答されているので、ここでは他の例を挙げてみます。
The university curriculum was so different from high school that it took me some time to get used to it.
とすると、「大学の[カリキュラム](https://eikaiwa.dmm.com/uknow/questions/114459/)が高校までと違いすぎて慣れるのに時間がかかりました。」となります。
参考になれば幸いです。