Green’s Dictionary of Slang

oneself, i.e. yours truly n.

1943–44		in G. Legman Limerick (1953) 74: There was a Hell’s Kitchen Y.T. / Who said to two boyfriends, ‘Aw, gee.’.
2001		K. Sampson Outlaws (ms.) 27: It was Y.T. he was looking at, searching for my reaction instead of looking at the package.
2013		K. Sampson Killing Pool 112: Those Unthank girls being a particular soul-love for YT.