I grew up near Millville / Vineland in South Jersey in the 90s and the kids on my soccer team (we're talking from the age of like 13 up to 18) would say "jawn"

I grew up near Millville / Vineland in South Jersey in the 90s and the kids on my soccer team (we're talking from the age of like 13 up to 18) would say "jawn" at least 100 times a day. Never heard it from adults though.