The applicant shall also file with said petition proof of his good character, which proof must be made by at least two citizens of the county who know his standing: Provided, however, proof of good? character shall not be required when the application is for the change of name of a child under 16 years of age. (1891, c. 145; Rev., s. 2148; C.S., s. 2973; 1963, c. 206.)