The 23-year-old left-hander was called up on Tuesday from Triple-A New Orleans, after posting a 2.63 ERA (47 ER in 161 IP) in 27 starts between New Orleans and Double-A Jacksonville.
Flynn said that after getting an invitation to Spring Training with the Marlins, he wondered if he would get his first callup in 2013.
"I had a pretty good year and everything, and you hope when you get a big league invite to camp [that your debut] comes around this year. … I was really hoping to make it happen this year and get my feet wet at the end of the season."
Flynn will get that opportunity in a ballpark that he has always admired.
"To find out it was [going to be at Wrigley Field] was even better," he said. "It's a great ballpark, a historic ballpark, and I'm a real big fan of baseball, so it's one of those things that I couldn't ask for more."
Flynn credits his mother, Michele, with helping him find the right coaching growing up after his father passed away following a car accident.
"It was pretty much Mom trying to find me good coaches," Flynn said. "Mom [was] always trying to find me the right pitching lessons. … just always supported [my dream] and kept it going."
Flynn said Wednesday will be a day he won't forget, but not only because he'll be throwing his first pitch in the Majors.
"[I'll] absolutely [be thinking about my dad]," he said. "It'll be a good day. I want to make the most of it, enjoy every aspect of it, and soak it all in."
Manny Randhawa is an associate reporter for MLB.com.