Miyata makes fine bikes, this looks like one of the lower MTBs in their range. An older MTB with city tires can be a very good and practical commuter, and there's not much demand for them so they are often cheap. It probably would fit you, but wouldn't hurt to go try it out just for info-gathering, unless you know for sure what your size is. Generally a 19" MTB is considered "medium" and at 5'4" it could be a bit big for you. Depends on your location, but for $160 I think you can do better than this one...in my town it would be a "fair price" (but my town is unfairly priced on everything).
Looks like it could be a 1991 "elevation 100":
http://4.bp.blogspot.com/_whtVpXkKwl...0-h/img265.jpg