My size is almost identical to yours, and I'm trying to get tests to narrow down the cause of my bone loss, as well as my true fracture risk at this point. I'm learning about these things in order to be able to have an informed discussion with my doctor on my course of treatment.
Because I'm petite, I feel that I need to be extra cautious.

Dr. Keith McCormick's book, Great Bones is the osteoporosis "Bible" which includes detailed explanations of all of the tests, how and when to use them, and why they are important.

Just last night I watched a YouTube video of an interview with Dr. McCormick hosted by Dr. Margie Bissinger titled "Bone Turnover Markers and Osteoporosis. It does a great job of explaining the various tests.
You can view it here: https://youtu.be/eZIgvcM9Ous?si=l9yyn4BhkeXPV31X.

Based on my understanding of each, I'll summerize what TBS and CTX are.
TBS (Trabicular Bone Score) is a measure of bone quality done through a software add-on used during your DEXA scan. It measures bone quality. TBS combined with your T-score provides a better indication of your fracture risk than the T-score can on its own.
CTX (C-terminal telopeptide) is a measure of how quickly your bone is breaking down (resorption/osteoclastic activity). This is helpful before treatment to narrow down the cause of bone loss, and as a measure of the effectiveness of treatment.

Here's some info on both directly from the Mayo Clinic:
TBS:https://www.mayoclinic.org/medical-professionals/endocrinology/news/new-tools-to-predict-fracture-risk/mac-20430573
CTX: https://www.mayocliniclabs.com/api/sitecore/TestCatalog/DownloadTestCatalog?testId=83175