It won't be until/unless someone adds it. It may also be there already but under a different name than the one you know.
Did you check the base Cemetery Map to see if there was a marker at the location of the cemetery where you know it to be? If not, you can easily add it. There are various posts and tutorials on how to do it but quick versions is:
1. Go to Cemetery Map.
2. Pinpoint the correct location and magnify. If not marker already there or very close by, then
3. Click ADD CEMETERY. A dialog will follow for you to add the appropriate information. It will even detect if there is another cemeter very close that might be an existing duplicate. Think carefully at this point and try to not create an unneeded duplicate because once you do, only BG support can delete or merge data with duplicates. If you are sure of the location, name and not a duplicate, then complete the process.
4. Add any information about the place (history, web site, church affiliates? ) that you know in the Information sections and complete the Add.
5. It is possible to add a cemetery while actually in the site, but better to do it in advance if you plan to go there to take photos.
6. If this cemetery is not already in the BG system, that means no photographs have been taken there within BG, so go forth and take the images if you can.