Vocal interjections appear in speech before they appear in print. That said, the earliest evidence we have for oops being written down comes from 1921, in the Washington Post. The etymology of oops is not certain – it may be a shortened version of upsidaisy (dating to 1862, and a fanciful variant of the earlier up-a-daisy) or may simply be a natural exclamation without any linguistic etymology.(с)
Отчего-то я думал, что это новодел.