"I walked in with my twins [Harper and Finley, 3], looked around, and I gasped. I couldn't tell if I was going to laugh or cry," she tells PEOPLE.
The exhibit, called Elvis ... Through His Daughter's Eyes, opened Wednesday (Lisa Marie's 44th birthday) and features childhood mementos including her crib, first baby shoes and a gold ID bracelet her father gave her, among other artifacts.
"It was like that show This is Your Life," she says. "I walked in and there was my tiny little first record player, my first faux fur coat, the key to the golf cart my father had given me for my birthday that I probably hadn't seen in 35 years."
Presley adds that she's grateful the archivists at her childhood home have preserved her things. If they were in her possession, she says with a laugh, they'd have gone missing. "I don't trust myself. If my head wasn't attached to my shoulders, I'd have lost it."
She is, however, doing her best to document the lives of her daughters with musician husband Michael Lockwood.
"My older kids [model Riley Keough, 22, and musician Benjamin, 19,] wish I had more photos of them when they were little," says Presley. "So we're constantly photographing the twins because we know how quickly it goes by."
Life with Her KidsPresley says she relishes every moment she can spend with her youngest children.
"Our life revolves around them and they dictate us and everyone around us. It's kind of about them and they're doing really well," she says. "I don't want to put them in school just yet – I want to keep them to myself as long as possible!"
The twins will hit the road with Presley when she tours to promote her next album, which was produced by T Bone Burnett and feels "more rootsy and organic" than her previous efforts. "They love to travel. They're little gypsies," says Presley.
She's also trying to convince her son Benjamin, a bass player who is the spitting image of his grandfather, to join her touring band.
"We haven't ever worked together but he's the one person who can get away with being a certain way with me and talking to me a certain way that no one else could get away with," she says with a laugh.
"He kind of runs me a little bit. He's really strong-minded and he will tell me what's what. It would be interesting, because if we butt heads, we really butt heads, and honestly, I'd back down. He has that over me."
"Elvis ... Through His Daughter's Eyes" is featured on Graceland's VIP tour and will remain open for two years.