And yes, the apostle Peter knew he would die(sleep) prior to the end of the age....
John 21:18 Verily, verily, I say unto thee, When thou wast young, thou girdest thyself, and walkedst whither thou wouldest: but when thou shalt be old, thou shalt stretch forth thy hands, and another shall gird thee, and carry thee whither thou wouldest not.
19 This spake he,
signifying by what death he should glorify God. And when he had spoken this, he saith unto him, Follow me.