Peter Quill (Marvel Cinematic Universe) - Wikipedia

Star-Lord (Marvel Cinematic Universe), Heroes and Villains Wiki

When did Peter Quil first become StarLord? Why did his mom call him that in her letter? - Quora

Guardians of the Galaxy Vol. 2 - Wikipedia

Star-Lord, Marvel Cinematic Universe Wiki

Guardians of the Galaxy Vol. 3 - Wikipedia

The Guardians of the Galaxy Holiday Special - Wikipedia

Star-Lord (Peter Quill), Characters

MCU: Peter Quill / Characters - TV Tropes

According to the MCU wiki, Peter Quill is about 40. However, it appears that the selection of music and audio tech suggests he's about a decade older, closer to Tony Stark's age.