Unfortunately it is generally the opinion that the Sphinx is at least 1000 years older than the 18th Dynasty, more likely around the time of the 4th Dynasty or earlier. Thus around 4,500 years ago. See various opinions at this Google page:
https://www.google.com/search?client=firefox-b-1-d&q=how+old+is+the+egyptian+sphinx
My bad, somehow I had the impression they were talking about reconstructing the face of the Sphinx, but they were reconstructing Amenhotep’s face from his mummy xrays. Nevertheless if Egypt interests you, you will find interesting information at my link.