That's an awesome NSV!!
I take my RHR once a week.. when I was at my highest it was usually around 68/70.. and now, its on the low side.. I've had readings at 50 and 48, lol. Randomly itll be in the 60's, generally when I'm angry at my MIL, but its usually always between 53-55.
Which, is great, I guess. My doc isn't worried about it, as I have abnormally low BP as well.. it runs in the family.