"This past year has made me realize how much I took my relationship with him for granted," the singer, 17, tells the San Francisco Chronicle of her sibling, who is two years younger.
"I've only been home a week and a half since the year started, and I really miss him," she says. "He knows everything about me. And, unlike a boyfriend, I know he won't walk away."
She wants the body adornment to be "in a nice script," and is thankful it's a short moniker. "It's not like his name is Bartholomew or anything," she says.
"Tattoo" is the first single from Sparks's self-titled debut record, which came out last week. After shooting the video, Sparks suggested to her mother, Jodi, that they both get tattoos to celebrate.
Voting RightsJodi's response: "I'll go get one with you when you're 18." (Mark your calendars: Jordin turns 18 on Dec. 22.)
Sparks doesn't have many other major plans for turning 18, though she does earn one big right – and plans to take advantage.
"I do get to vote," she says. "I will be voting."