Meg Jay, assistant clinical professor, Curry School of Education, "The Defining Decade: Why Your Twenties Matter – and How to Make the Most of Them Now." Twelve Books.

Here's some sobering advice for new college graduates: After the pomp and circumstance fades, the most important decade of life gets under way, according to Meg Jay, a University of Virginia psychologist who specializes in adult development. In her book, "The Defining Decade," she argues that 20-somethings have been caught in a swirl of hype and misinformation, telling them there's no hurry to find themselves.

Jay, an adjunct professor in the Curry School of Education, uses real stories from real lives to give advice on the crucial – and often difficult – first years of adulthood. The book provides the tools necessary for young adults to make the most of their 20s, and shows readers how work, relationships, personality, social networks, identity – and even the brain – can change more during this decade than at any other time in adulthood.

"We know that 80 percent of life's most defining moments happen by age 35," Jay recently told NPR's Rachel Martin. "We know that 70 percent of lifetime wage growth happens in the first 10 years of a career. We know that more than half of Americans are married or living with or dating their future partner by 30."

In her book, she advises, "There are no guarantees. So claim your adulthood. Be intentional. Get to work. Pick your family. Do the math. Make your own certainty. Don't be defined by what you didn't know or didn't do."

Jay also maintains a private practice in Charlottesville. A 1992 alumna of U.Va.'s College of Arts & Sciences, she earned a doctorate in clinical psychology and in gender studies from the University of California, Berkeley.