As stated in the text, "Some of the remarkable talents and productivity of people with special gifts develop early and continue throughout life; in other cases, a person's gifts or talents are not noticed until adulthood. Occasionally, a child who shows outstanding ability becomes a nondescript adult." In other words, someone who is gifted may be gifted throughout their lives. The talent can be considered a gift one day, but another day the definition of the gift has changed. It all depends on the culture around that person to determine if they have a gift or not. Some people will find a gift at a young age, while others as they are adults.
Resource:
Hallahan, D., Kauffman, J., & Pullen, P. (2013). Exceptionality and Special Education. In Exceptional Learners: An Introduction to Special Education (Thirteenth ed., pp. 377). Pearson.