Chappy1978, welcome to the Forum!
There are exactly 100 genuine inverted Jennies. They all came from one sheet and all but one of them are accounted for.
The likelihood that you have that one is not very high.
That being said, look at the back of the stamps. Does the one on the left have shiny gum? A scan of the front and back of it would be helpful.
The one on the right is either one of the stamps which were sold by the USPS (and are still on sale) to commemorate the inverted Jenny, or it is a forgery.
The reason I say this is the only stamp unaccounted for came from the McCoy block, which was stolen in 1955 in Norfolk, VA from the frame at the APS Stamp Show. The block has been broken up and three of the stamps recovered. The one missing stamp does not have margins as large as the stamp on the right.
If you think this is the real stamp, please contact the American Philatelic Center. There is a reward being offered for the return of the stamp, which Mrs. McCoy bequeathed to the American Philatelic Research Library, should it ever surface.
One of the stamps did surface in late 2015 in Ireland. The grandson who
inherited received the reward for that stamp when it was returned to the APRL at World Stamp Show 2016.
Hope this helps.