IOWA CITY — When Iowa City High senior Megan Bywater was 1 1/2 years old, she achieved mobility no one expected. With the help of braces and crutches, she walked for the first time.Since that day, she has been exceeding expectations.Bywater participates in choir and band at City High. She loves to play games and spend time with family and friends.Many things have shaped Bywater, and only one of those pieces is her spina bifida.The Mayo Clinic website notes spina bifida occurs when there are problems with the development of the spine and spinal cord.