I used to eat that all the time when I was little. That takes me back.
I was always eating those when I was a kid. That really brings me back.
「しょっちゅう」は “all the time” “frequently” “often” “constantly” “always” などになります。「子供の頃」は “when I was a kid” とか “when I was little” とかだとカジュアルな言い方になりますが、 “when I was young” とか “when I was a child” だともうちょっとフォーマルに聞こえます。
I used to eat that often when I was a child. How nostalgic!
ご質問ありがとうございます。
"I used to eat that often"＝「私はそれをしょっちゅう食べていた」
"when I was a child."＝「私が子供のとき。」
（☆"child"の代わりに"When I was little"=「私が小さかったとき」とも言えます）
"How nostalgic!"＝「懐かしい！」
☆「懐かしい」を"Good old times"＝「古き良き日々」と言うこともできます。
Boy, that brings back memories. I used to eat that all the time when I was a kid.
That reminds me of when I was a child. I ate that quite often.
ーBoy, that brings back memories. I used to eat that all the time when I was a kid.
「懐かしい。子供の頃よく食べた。」
that brings back memories. で「記憶を呼び起こす」＝「懐かしい」
used to ... で「よく…したものだ」
ーThat reminds me of when I was a child. I ate that quite often.
「子供の頃を思い出す。それをしょっちゅう食べていた。」
That reminds me of ... で「…を思い出す」
ate ... quite often で「…をしょっちゅう食べた」
ご参考まで！
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