Before you know it, life can go by in a flash.
"I'm ready for it to be over," he told E! News ahead of The CW show's ninth and final season. "And that's not for any negative reason. It's like when you're getting ready to finish high school and—granted I don't know what college I'm going to after this, I might not get into college—but you're excited to wrap up and move on to the next phase of your life."
Gustin, who shares 17-month-old daughter Juniper Grace with wife LA Thoma, added, "I'm ready emotionally and my family is ready to just kind of move into the next chapter together."
He's not entirely sure what that next chapter has in store—but not having it all mapped out is not exactly new for Gustin. As the 33-year-old explained, he's never put too much thought into The Flash's inevitable conclusion since the Arrow spinoff sped onto screens in 2014.
"I never had a real expectation, I've never tried to visualize how it would end after all these years," Gustin shared. "So, I have no idea what to expect from this last one, whatever script I receive in my inbox is what I'll accept as our story and then move forward with."
And when it's time to say goodbye for good, the actor doesn't think he'll be able to walk off set with his character's iconic super suit. Still, he'll always have the memory of working alongside Candice Patton, Danielle Panabaker, Carlos Valdes, Tom Cavanagh and the rest of the crew once production wraps on the Vancouver-shot series (of which they are currently filming the penultimate episode).
"One thing that's stayed consistent doing this for so long is I laugh every day, and that's really special," Gustin noted. "There's been a lot of moments this season where you're standing around laughing with somebody, having some trivial conversation and then you realize we won't all be in a room together ever again."
Just like his character, he's experienced a lot of life over the course of 184 episodes. "I started doing this when I was 23 and I just turned 33," Gustin elaborated. "So, I've had to learn lessons the hard way and fall on my face and embarrass myself and grow up in front of and with a lot of these people. So, it's gonna be really weird to not see a lot of these people every day anymore."
But while The Flash the television series might be coming to an end, DC does have plans for a movie version of The Flash. Still, for millions of fans all around the world, Gustin will always be Barry Allen.
"I'll get to be The Flash forever even when this ends," he shared. "We couldn't have done this this long if we didn't have people supporting us as much as they had over the years, and it's really shaped who I am."
For being the fastest man in the world, he sure enjoyed that walk down memory lane.
See Grant Gustin's last lap as Barry Allen when The Flash returns for season nine, Feb. 8 on The CW.