We can only guess which one you will need; there is no certainty based on the age of the home. Even though four-prong wiring for ranges and dryers was required by the National Electrical Code in 1996, that edition of the code may have been adopted later by your jurisdiction. Also, wiring performed by amateurs and not inspected may be installed as 3-prong, and wiring installed before 1996 could be four-prong.
When you install the cord, you'll need to pay special attention to the connection block on the back of the range.
There will be a jumper -- usually a strip of brass -- back there.
If you are using a three-prong cord, this jumper must be placed between the center "neutral" terminal and the green grounding screw. If the jumper is missing, you will need to get a replacement jumper from an appliance repair shop.
If you are using a four-prong cord, this jumper must be removed. There should be no connection between the neutral terminal and the frame of the range. Fasten the jumper to the range somehow so it can be reused if you move somewhere that requires a three-prong cord.
The four-prong cord is safer, as the neutral and ground are separated. In many cases where a three-prong outlet is installed, both a separate ground and neutral wire are available inside the electrical box behind the outlet. You may be able to have an electrician upgrade the outlet to a four-prong version.