The 1851 Census indicates that Charles Curtis was born at "Linn" now known as King's Lynn. The only Charles Curtis baptised in the area around the right time that I could find is Charles Sheridan Curtis, born in August 1795. This should have made him 45 for the 1841 Census but he is shown as 35 (ages were generally recorded to the lower multiple of 5 years). His age in 1851 is shown as 53 but this may have been rounded down to reduce the age gap with his much younger second wife. Maybe she didn't know his true age as she reported his age as 55 for his death certificate in 1856.