Sunderland's voyage will take her more than 24,000 miles.
Last year, her brother Zac became the first person under the age of 18 to complete the voyage solo.
"I'll definitely be keeping a journal documenting everything and hopefully write a book when i get back, probably not going to have a lot of poems," Abby said.
A 16-year-old Australian girl is on a similar journey. She's been at sea for nearly 100 days now.