Shaunta-Maé Alexander had a long journey to the start line of Sunday’s United Airlines NYC Half, not just because she’s from Sacramento, Calif. The 35-year-old children’s book author and aspiring actress has overcome a lifetime of illnesses — even paralysis — to run her first half marathon. More than 27,000 athletes are expected to take the 13.1-mile tour of Brooklyn and Manhattan hosted by New York Road Runners. Alexander is part of the…