て初めて

て初めて is used to say that something happens for the first time or becomes true only after the action in the preceding clause occurs. It conveys a sense of realization or change in understanding, often with a contrast to before that moment. It can imply that before doing the preceding action, the situation was different or not understood, and only after that action did something become evident or possible. The action in front of て is typically a verb in its て-form and refers to the experience that leads to a new state or awareness.