Breakdown of Перед экзаменом я всегда нервный.
я
I
всегда
always
экзамен
exam
перед
in front of / of (with fear) / before (in time)
Questions & Answers about Перед экзаменом я всегда нервный.
Why is экзаменом in the instrumental case here?
The preposition перед (before) requires the instrumental case when referring to a point in time or a physical position. Since экзамен (exam) is a masculine noun ending in a consonant, we add the ending -ом.
Why use the adjective нервный instead of a verb?
Where is the verb "am" in the Russian sentence?
In Russian, the present tense of the verb "to be" (am/is/are) is normally left out entirely. You literally say "I always nervous". If you wanted to say this in the past tense, you would need to add the verb: я всегда был нервный (I was always nervous).
Should I use a short-form adjective here since being nervous before an exam is a temporary state?
That is a great instinct! Generally, short-form adjectives are used for temporary states while long-form ones are for permanent traits. However, the short form of нервный is extremely rare and sounds unnatural in modern spoken Russian. Stick to the long form нервный or use the verb нервничать.