We really dislike the concept of defining generations, as all people within any generation are unique and different. Using generation classifications tends to stereotype all of its members when, in fact, whatever attribute is being ascribed to that generation will not apply to the entire generation and that attribute will apply to many members of other generations. For example, there is a large difference on multiple dimensions for Millennials. A 24-year-old single medical student in Washington, D.C. is a lot different than a married 29-year-old cook with children in Ames, IA, who is a lot different than a 35-year-old married stock broker with no children living in Manhattan.
Nevertheless, we seem to be forced by all the research and press to use the different generation categories at some point. So, based on Pew Research's definitions, here's the age range for each of the adult generations in 2019.