。
She's an early riser.
Literal
She [topic-は] early-rising is.
早起き is a compound noun from 早い (early) and 起きる (to get up), used here as a predicate with the copula だ. This pattern — packaging a habitual trait into a single compound noun rather than using a full verb phrase like 早く起きる — is common in Japanese for describing personal characteristics.