Mri read l3-l4 there is early darkening of the facets.l4-l5 there is mild right facet degeneration.

Arthritic change: This simply refers to mild arthritic change in the joints of the spine. It is very common and means very little about your long term prognosis assuming you have back pain.

Probably nothing: Mild facet "degeneration" (ie arthritis) is very common at that level even at your age. Darkening is probably meaning sclerosis, which also goes along with this, but is kind of an unusual way to describe it.