My great grandmother came to the US alone-first class in 1859. She is listed on the passenger list as 8 years and younger-which I assume means lower price. She was 11 according to her birth certificate. My Mother did the same thing-when we flew I was always 12 even if I was 20!
By the way, my great grandmother's mother had died, and she was coming to an Aunt and Uncle after her father remarried. Sally Bruckheimer