Blake Shelton turns 40 years old this month. His June 18 birthday and his new exhibit at the Country Music Hall of Fame and Museum have made him a bit wistful for days gone by — and the things that went with it.

Simply put, the “She’s Got a Way With Words” singer wishes he’d held on to more. “(There have been) Really cool, sentimental things that I should have kept along the way. Now that I’m getting older it sucks to know there are things I didn’t hang onto,” Shelton told media prior to the grand opening of his exhibit.

“You get a lot of cool things when you do what I do,” he added, encouraging any young singer to become a packrat.

Some of Shelton’s cool things are on display. Fans will find his first song lyrics, which are part of an old notebook he can’t believe he kept. Early outfits, career milestones, awards and photographs from every decade of the singer’s life and career are encased for fans to see through November. You won’t see his most cherished possession, however, as he can’t find it!

“I bought a black Takamine, cutaway guitar. The same one I saw Garth Brooks playing on his first television special,” Shelton recalls. “I called my mom and said ‘Do you have that guitar?’ And she goes ‘No! And you might know where it is if you didn’t throw everything away and give it to everybody!’”

Shelton calls the exhibit a “career highlight” and seems truly humbled by the honor. He jokes that he hoped he might get a full tour of the museum, including what’s not on display.

“I do wanna go through the music room because there’s a lot of sh– I can’t get on iTunes that I bet you guys have up there,” he remarked. “Y’all got Garth up there? Because I can’t find him on iTunes. Unbelievable. It’s 2016 for God’s sake.”

Turning 40 may have made Blake Shelton wistful, but age hadn’t dulled his sharp sense of humor.