for the first time in (period of time)
Expresses that an action happens for the first time after a certain period has passed.
Use this pattern to say that something has not happened for a certain length of time and that it happens now for the first time. The noun must be a duration, like 三ヶ月 (three months) or 二年 (two years). You cannot use it with a specific point in time, like 5時 (5 o'clock). For example, 三ヶ月ぶりに means 'for the first time in three months.' The action you describe is the one that is happening after that gap.
This pattern often appears in casual conversation, but it is also used in writing. It carries a feeling that the speaker is happy or surprised that the event finally happens again. You might hear it with verbs like 会う (to meet), 食べる (to eat), or 行く (to go). Remember that the noun must be a duration, and the pattern is ぶりに followed directly by the verb.