Teefey, 42, shared an adorable video of the pop star, 25, from 1997 when the singer was just 5 years old. In the video, Gomez, wearing two pigtails, is seen showing off her sass as she talked to her mother on the phone and complained about homework.
“@selenagomez talking to me on the phone when I was at work asking about her day at school,” Teefey wrote in the caption. “My sassy, independent, boss lady, adorable gigantic piece of my heart, first born love.”
“Gracie is exactly like this. Diabolical. XO,” the mother of two continued, referring to her second daughter, 5-year-old Gracie Elliot. “My girls are born leaders. Why do they grow up? Her sweet little eyes and massive eyelashes.”
In the footage, Gomez tells her mother about a homework assignment she had to do again at her teacher’s request.
“My teacher said I gotta do all this stuff again. I gotta do it by myself,” the tot said in the video. “I’m going crazy, you gotta help me over here! You better girl.”
Gomez’s father is Ricardo Joel Gomez. Teefey and Ricardo are divorced and Teffey married Brian Teefey in 2006 and shares Gracie Elliot with him.
“It’s more complicated than just fighting over a guy,” the source said. “Mandy and Selena have had their ups and downs before. This isn’t the first time.”
While the two weren’t speaking, the insider said Gomez “also wants to give her mom some space.”
“When they fight, they fight hard,” the source said. “But when they love, they also love hard.”
Gomez reunited with Bieber last year and spent New Year’s with the “Sorry” singer in Cabo San Lucas, Mexico after she split with The Weeknd (né Abel Tesfaye) in October.
RELATED VIDEO: Selena Gomez Isn’t Currently Speaking to Mom Mandy Teefey and Wants to ‘Give Her Space’: Source
A source told PEOPLE at the time that the two were “doing great.”
Weeks later, Teefey admitted she was “not happy” about her daughter’s rekindled romance with Bieber during an interview with Gossip Cop.
She also revealed she had not spoken to Bieber in “years,” although she said she knew Gomez was old enough to “make her own choices.”
“Selena can live her life however she wants as long a she is happy, safe and healthy,” Teefey said. “She is 25-years-old and knows what is at stake with her health.”