I will never tire of posting the panels below, which are from 1968, and precede the involvement of the aforementioned writers by years. Keep in mind, being highly advanced robots equipped with bio-sensors, amongst other things, Computo and his Cybertrons were not just making an arbitrary statement; they were assessing and classifying Jean.
The breadth and scope of Jean's growth during the first 66 issues of X-Men are often overlooked. Even Stan Lee had her doing things, such as telekinetically disassembling and reassembling a complex piece of machinery (in this case, a rifle) in mere seconds, that would later be attributed to the Phoenix Force's influence. The rapidity and level of growth Jean experienced under Lee's pen alone was breathtaking. After all, his very first impressive feat for Jean is found in issue #1, where she uses her telekinesis to redirect an active missile into the ocean. He also established her ability to fly using her telekinesis, depicted her overpowering and toppling a pair of Sentinels, catching Quicksilver mid-run, overwhelming the Scarlet Witch, and lifting and paralyzing Juggernaut, amongst other impressive feats.