The issue is not the salvation of St. Peter but the commission of St. Peter, and on that score the scripture informs us of a significant difference between St. Peter and you or me.
No, of course, it wasn't merited. Grace is something God offers to all, for He wants to save all (1 Tim 2:4), but not all will be saved; certanly not for lack of God's love! Not all will be saved, because not all will accept God's grace; certainly not for lack of the knowledge of God (Heb 8:10-11).
Perhaps +Peter was like you and I are, but he surely achieved his likenss to Christ before he died, which we can only desire at this point. If for no other reason, he deserves our owe and respect for that.
Also, your definition of "being saved "is somewhat odd. Salvation is what is at the end ouf our journey to God, not at its beginning: "but he that endureth to the end shall be saved" (Mat 10:22)
Don't flatter yourself that accepting God (in words) means life-ever-lasting, a sure ticket to heaven. That is where Luther erred, giving in to the master of deception, Dr Feelgood, the serpent, Lucifer, when he formulated his famous "pecca fortiter..." nonsense, accepting God but giving in to evil. The original "don't worry, be happy" theme.