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general::
Phrase(s): get ahead of oneself
Fig. [for someone] to do or say something sooner than it ought to be done so that the proper explanation or preparations have not been made. • I have to stick to my notes or I will get ahead of myself in my lecture. • When he bought a new little bicycle before the baby was born, he was getting ahead of himself.
McGrawhill's American Idioms And Phrasal Verbs