You have low bone mass but good microarchitecture.
This is the silent part of osteoporosis. Your network of trabecular bones are still intact. The loss of density can eventually results in disconnection. You don't fracture, but you become more vulnerable to compression.
https://www.researchgate.net/figure/Cancellous-bone-occurrence-and-macrostructure-as-illustrated-here-with-the-femur-of-a_fig1_328641052
It looks at though at 56 you've begun to lose bone density and you are catching osteoporosis before it causes permanent damage to your bones. I'm guessing that the loss of estrogen and that the next couple of years would be the time of greatest loss unless you engage treatment.
You are in a great position to protect your bones.