To add variety to the guesses, I'll say MS63 for fun, even though it's probably a 65 or 66 and might be a proof.
The easiest way to get it right is to guess every possibility at once! It's somewhere between Poor 01 and MS 70, or Proof 01-70
It may well be a proof, but I'll go with MS67, maybe 66+. The details are amazing and the toning looks natural.
I agree with those who recognize this coin as PR64. However, it is possible the weak area on the shield is possible wear. A closer examination will settle whether it is PR58, or PR64.