And if you are the Duke of Cambridge, much of your previous years have been spent with Kate Middleton.
After taking a break in their relationship, the couple became engaged in 2010.
After graduation, William and Kate kick off their careers.
Kate gets a job as an accessories buyer for fashion chain Jigsaw, while the prince joins the elite Royal Military Academy at Sandhurst.
It was at the Cheltenham Festival, the great Spring celebration of National Hunt racing, that it first became clear.
Dressed in matching, decades-older tweed outfits, William and Kate looked unhappy and out of sorts, in comparison to an event one year earlier when they had been spotted kissing in public for the first time.
Disaster strikes when it's reported that the pair have split.
There was no longer any disguising the fact that William was unsure of his future with Kate.
In 2002, they move into a student house with two other friends and by Christmas 2003, romance blossoms when Kate splits from her previous boyfriend.
Their relationship becomes public after they are pictured skiing in Klosters together and in June 2005, the royal and his new girlfriend are pictured looking very much in love on the day of their graduation ceremony.
By the time Kate flew to Ireland with her mother on April 3, their four-year relationship was over.
Kate was devastated, but instead of weeping at home, she kept herself busy.