Whenever you are writing or talking about a person be specific. First names are rarely specific enough, particularly in some families. First and last names are best, perhaps combined with a date of birth or date of death.
My mother has three Aunt Ruths. It usually took more than just “Aunt Ruth” to know to whom someone was referring. Sometimes it was clear from context, but not always. Don’t create additional confusion in the records you leave behind. Be specific.