Green’s Dictionary of Slang

(Aus.) to feel pleased with oneself.

1919		C.J. Dennis ‘The Vision’ in Chisholm (1951) 115: I was feelin’ fine this mornin’ when I started out to work; / An’ I caught myself high-steppin’ with a boastful sort of jerk.
1926		Lucille Hegamin ‘Here Comes Malinda’ 🎵 Steppin’ high / With Miss Malinda slow, / You won’t last; / Is she fast? / She’s just a human dynamo!