。
She was nearly late.
Literal
[topic-は] almost be-late [about-to-ところだった].
もう少しで...ところだった is the canonical Japanese 'near miss' construction — 'just a little more and X would have happened.' Crucially, the event did NOT happen: ところだった describes a counterfactual, the brink. Drop もう少しで and you can still say ~ところだった alone (was about to X, but did not), but the もう少しで puts the close call in sharp relief — 'one step closer and...' Common pattern in confessional anecdotes; pairs with verbs of misfortune (遅刻する, ぶつかる, 落ちる) far more than with positive outcomes.