Not a stupid question at all. Very wise to ask it, in fact.
You should definitely check this before investing. Do you have ANY old desktop monitors in your house that you can plug in and try?
Or, a TV with HDMI or DVI inputs that you can plug in as a temporary external monitor and calibrate?
Or failing all that, a nearby friend or relative who would let you come over and try plugging in their desktop monitor and calibrating it?