Not for me, just the opposite really. I've aced literally every class for the past 3 years (> 100% as a final course grade). I did end up with a median MCAT (509) but to be fair, the mcat isn't as much about recall (not to mention I supported 3 households while studying and taking care of my mom and had effectively 3 weeks worth of actual study time). I am consistently the top scorer on every test in classes of 200+, and I attribute that to the fact that my recall is so good (because by being at a big university, most of the test questions are not critical reasoning questions, but rather rote recall).
Could be genetics, but I honestly attribute a lot of it to a low inflammation diet, regular exercise, and adequate sleep (the last being the hardest to ensure). I feel absolutely smarter in my 40's than I ever did in my 20's. My grades are reflexive of the fact that this is more than just a feeling, as my 20 year-olf-self performed well, but was never "top of the class." At this point, the only people who intimidate me are toxicologists, all of which seem to have some next-level nerdiness going on that I haven't quite reached yet, though that is the ultimate goal.
Examine your diet and exercise regimen and see if there isn't some improvement you can make. As a non-trad your advantage should be that you can afford to eat organic greens instead of ramen.