In English we would say, ‘I go at my own pace.’ ‘My pace’ is never used in the third person, so when referring to another, we would say, ‘He goes at his own pace.’ The often-heard phrase, ‘She is my pace,’ is nonsensical in English and should be, ‘She does things at her own pace’ or, ‘She does things in her own time.’ ‘My pace’ is Japanese.
マイペース
英 語では「I go at my own pace」と言います。他人のことを言うときは、「He goes at his own pace」と言います。「彼女はマイペースだ」を直訳した「She is my pace」は英語では意味をなしません。「She does things at her own pace」や「She does things in her own time」(彼女は自分の都合のいいときにことをする)と言います。「マイペース」は英語ではなくて日本語の単語です。