。
It seems she's getting nervous about her first lesson.
Literal
She [topic-は] first [genitive-の] lesson [about-に] nervous becoming [seems-ようです].
神経質 ('nervous, sensitive, high-strung') is a な-adjective with two main shades: an intrinsic temperament ('a high-strung type') and a temporary state ('feeling jumpy about something'). 神経 ('nerves') + 質 ('nature, quality') gives 'nerves-nature' — the disposition of having frayed nerves. ~になっている ('has become / has come to be') frames the nervousness as a state she's settled into; ~ようです ('seems') closes with the speaker's inference, not direct knowledge. 授業 ('class, lesson') is the school-context word, distinct from レッスン (loanword, often for music or sports private lessons).