In Star Trek IV, Kirk says "I'm from Iowa, I only work in outer space" which IMO is legit even if TOS Kirk was born in space, since he was raised in Iowa. I have an aunt who was born in Africa but raised in England and she doesn't consider herself African.
They did consider calling the ship the USS Iowa as a fudge workaround at one point, but it wasn't necessary. I like the idea the Kelvin was en route to Earth and Jim was born premature (January 4, since his non-canon TOS birthday is in March) due to the rather stressful situation of the Romulan attack.