Fresh
な adjective
New and fresh is fresh (has to be new if you want it to be fresh, after all).
しんせん
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
前の職場では、止めろと言われるまでいつも残業していたので、毎日五時に退社するのはとても新鮮です。
I always worked overtime at my last job until I was told to stop, so it’s very new to me to leave work at five o’clock every day.