。
She's about my age.
Literal
She [topic-は] me [about-くらい] of age is.
A compact form of the equality construction — without 同じ. 私くらい ('about as [much/old/etc.] as me') uses くらい for approximate equality. Where 同じくらい would emphasize 'the same amount,' bare くらい more loosely says 'about the same range / about the same level.' Common in casual conversation when an exact match isn't important. Compare with 私くらいの背 ('about my height'), 私くらいの経験 ('about as experienced as me').