、。
She took a deep breath and then began to tell her story.
Literal
She [topic-は] deep-breath did [after-てから], life-story [object-を] tell-began.
Two notable grammar patterns stack here. ~てから ('after doing') establishes a sequence — she breathed first, then began speaking. ~始める (~はじめる, 'to begin to') is an aspectual compound verb marking the onset of an action. 身の上 (みのうえ, 'one's life story, personal circumstances') is a set expression for the events and circumstances of someone's life. 語る (かたる) is more literary than 話す — it means 'to narrate, to recount,' implying a deliberate telling.