I did that out of youthful folly (lit. as a result of youthful excess).
Receiving such an award from everyone is the greatest honor.
極致 refers to the ultimate, unsurpassed point of something (e.g. 美の極致), while 至り is specifically used in the fixed pattern ～の至り to describe an emotional or evaluative extreme.
Standard kanji form; used in formal and written contexts.
Noun form of the verb 至る (いたる, 'to reach, to arrive at'), meaning the point reached or the result.