No, you do not need hyphens for "great aunt." It is correctly written as two separate words. However, when used as a compound adjective before a noun, it can be hyphenated, as in "my great-aunt's house."
If you're using the phrase as an adjective (example "This easy-to-use remote is great!") then it will definitely need the hyphens. Otherwise, the hyphens are incorrect.
Some say yes, you do need a hyphen because the term great is integral to the definition of great-grandmother. Otherwise, a great grandmother is just a grandmother who is terrific. Other people see no need and d not use hyphens for this.
Your great aunt is your daughter's great great aunt. Your daughter is your great aunt's great great niece.
Your great aunt.
You Aunt is you grandson's Great-Great Aunt. Your grandson is your Aunt's Great-Great Nephew.
You granddaughter is a great great niece of your aunt. Your aunt is your granddaughter's great great aunt.
To your child, she would be a great great great aunt. If she is your mother's great aunt, that means she is your great great aunt, making her a great great great aunt to your child. I would just stick to calling her auntie or Aunt ______. :)
Your great-great aunt is your daughter's great-great-great aunt.
Your grandmother's sister is your great aunt
She is your Great Aunt in law!
You are your neice's aunt, your neice's children's great aunt, and your neice's grandchildren's great great aunt
Your Great Great Aunt