[stylin19a]

probably not.

Pres. Biden could not have entered Execution of Office until the current presidency ends at noon regardless of taking the oath of office early.

Oath of Office - no mention about when it can be taken.
Article II, Section1, Clause 8

Before he enter on the Execution of his Office, he shall take the following Oath or Affirmation:—"I do solemnly swear (or affirm) that I will faithfully execute the Office of President of the United States, and will to the best of my Ability, preserve, protect and defend the Constitution of the United States."

20th Amendment Section 1 only specifies when the current presidency ends - noon.

"The terms of the President and the Vice President shall end at noon on the 20th day of January, and the terms of Senators and Representatives at noon on the 3d day of January, of the years in which such terms would have ended if this article had not been ratified; and the terms of their successors shall then begin."

[WildHighlander57]

Ping to stylin19a ‘s post; PDJT could’ve gotten sworn in Saturday night, sometime today, or sometime before noon tomorrow; the 20th Amendment Section 1 only says when the current presidency ends.

https://freerepublic.com/focus/chat/4287546/posts?page=3735#3735