The greenish yellow color at the center tells you the plant needs more light. If there's any other location with more sun, your plant may recover. Just be careful not to put it outside in full blazing sun without some gradual adjustment. When these plants enter crisis some weird things can happen, but I think your observation is telling you something about how you're growing the plant.
Echeverias have an interesting relationship with light. They tend to grow in the higher altitude parts of Mexico (among other places). Which means they like direct sun (indoor sun is not direct if it has passed through a window, as the UV is filtered out) and can tolerate a few hours a day, but only if the temperature does not get too high. My general preference in our mild climate is to provide half a day of sun to most, esp. the large ones. Filtered light is great too. They get shade in the late afternoon and change visibly in size and color when the wall to their side starts to shade them more in winter. Those changes are a good guide to understand their normal cycle, the variation they exhibit through the seasons.
This time of the year the less sun-hardy plants tend to start complaining about too much sun and I move them to a different location with about half the total hours. The reason I know they need protection is because I have killed them before by not providing it.
There are a few other leaves that also seem about to fall off. What's wrong with it??
