From the F holes it appears to be in the style of a German Strad copy from the early 1900's to 1930. If you really want to know more, take very good, well lit close up pictures of the F holes, purfling (2 tone decorative stripe around the front and back panels), the scroll (both sides and back), the back of the neck so as to see any repairs or splices.
These would help in valuing the instrument. As Mojjax stated, look in the F holes with a flashlight for a label. It will most certainly not be a Stadivarius even if it says so. but if it's dated or not that would be informative. The instrument is in good shape and has been protected at least. Good luck and if you're interested in selling, I'd certainly entertain a discussion.