Yes, as the bride was not yet 21 years of age, she was not yet old enough to give her own consent to her marriage. Same would apply if the groom was not yet 21 years of age. In the 1970s that section of the marriage Act was altered to 18 years of age.
"Written Consent" became mandatory from 1925, under the NSW Marriage Act of 1899 as amended.
Cheers, JM