I have to write my test today even though I'm not that excited about it.
Test day is finally here, time to face the music.
ーI have to write my test today even though I'm not that excited about it.
「今日試験があるから、あんまり嬉しくないんだよね」
to write one's test で「テスト・試験を受ける」
excited で「ワキワクする・活気のある」
ーTest day is finally here, time to face the music.
「とうとう試験日だ。困難に立ち向かう時だ」
to face the music は「潔く受け止める・困難に立ち向かう」という意味です。
ご参考まで！
Today is finally the exam.
The exam is finally today.
Ugh, the exam is finally here.
「今日ついに試験です」は、直訳的に **Today is finally the exam.** または **The exam is finally today.** で表せます。
カナダ 
アメリカ合衆国 
