Hmmm I would have to go back and look, but that seems not too much less time (but maybe just enough less?) than what I usually do.
I have an hour and 11 minutes on Tuesday when I go through ERT Paris. I didn't think twice about booking it - ha, maybe I should have, since the Paris-bound flight out of Atlanta is the last of the evening (i.e. not as easy a rebound if I miss it).
I will go back and look at my last few flights - I know in May when I came home I had something like six HOURS, which I have never done before and obviously isn't comparable.
Edit to add - ok I went back and checked all my TUL-ATL-CDG flights back to 2014 (roughly comparable to AMS).
Layovers in Atlanta between arrival of flight from Tulsa and departure for Europe (CDG in this case, AMS for you):
Aug 2014: 2 hr 30 mins
April 2019: 1 hr 4 mins
Nov 2019: 1 hr 21 mins
May 2021: 1 hr 38 mins
Dec 2021: I bought a ticket with a 1 hr, 28-min layover. They cancelled the outbound Tulsa flight and rebooked me for all the next day ( New Year's Eve!) with a 3 hr, 48-min layover
June 2022: 6 hr 23 mins (I waited too long to buy my ticket, and that big layover brought the price down, so I sucked it up and went with it)
Nov 2022 (planned): 1 hr 11 mins
So -- I have never had a layover of less than an hour. Have had ones just over an hour that have gone perfectly fine.
Part of the thing with the 51 minutes that would make me nervous is, since you want to buy Premium Economy -- if you do have to catch a later flight out of Atlanta, will they have space for you in Premium Economy, the product you paid for ?
(It doesn't really make me any difference because I just fly main economy - all I would need is a seat. But if I had paid for Premium Economy, I would want to get that even if I got bumped.)