In your twenties
Definition 1 of 1
Pro Tip 1/3Age Range Specific
Refers to any age between 20 and 29, inclusive of both 20 and 29. 
He learned to play the guitar in his twenties.
Pro Tip 2/3Life Stage
Often associated with milestones or experiences commonly facing adults in this age group. 
She traveled the world in her twenties.
Pro Tip 3/3Cultural Views
In many cultures, being in your twenties is seen as a time for personal growth and exploration. 
In his twenties, he was still figuring out his career path.