It apparently has also appeared on a recent Abitur text, supposedly from an English original. I thought that was a really bad decision, because it will only encourage a slew of students to translate over-literally.
'Lyric(al) I' may be used occasionally, perhaps mainly by people familiar with German or other languages. However, it's really far from the best choice. Speaker, first-person narrator, narrative voice, narrative persona, the 'I' of the poem, any number of other choices are often more idiomatic.
Even if you felt compelled to translate 'lyrisch' literally, which I'm not recommending, it would surely be better to use 'lyric,' which is an objective term for the genre of shorter poems written from a subjective, emotional perspective (lyric verse), and not 'lyrical,' which is a subjective, descriptive term meaning beautiful, imaginative, flowing, songlike, etc. The two senses are occasionally confused, and back in the day of Wordsworth's Lyrical Ballads they were not as separate as they now are. But precisely in an English literature class, students should be made aware of the difference.