後で後悔しても後の祭りだと言ったよね

N5 後で ato de after N3 後 go afterwards, after, since then N3 後悔 koukai regret, remorse N3 祭 matsuri festival, feast N1 だと dato if it's the case

N5 後 go, kou / nochi, ushi.ro, ushiro, ato, oku.reru behind, back, later N1 悔 kai / ku.iru, ku.yamu, kuya.shii repent, regret, regret N2 祭 sai / matsu.ru, matsu.ri, matsuri ritual, offer prayers, celebrate N4 言 gen, gon / i.u, koto say, word, dire

N4 〜し shi Indicates multiple reasons or qualities, connects clauses or adjectives, means besides that, and also N5 〜で de Indicates where an action happens, means used, tool, cause, or material depending on context N5 〜と to Indicates company, quotation, natural condition, complete list, or direct connection between elements N5 〜の no Indicates possession, relation between nouns, nominal explanation, or turns a verb into a noun phrase N5 〜も mo Means also, adds another similar item, often replaces particles such as wa ga or o N5 〜ね ne Sentence ending particle seeking agreement, softens statement, similar to right or isnt it N5 〜よ yo Sentence ending particle adding information to listener, emphasizes statement, expresses certainty or warning