From left: Patricia Houston, Whitney Houston and Bobbi Kristina
Bobbi Kristina's first interview since the death of her mom Whitney Houston
is set for Sunday, but members of the 19-year-old's family have concerns about the timing of the one-on-one chat with Oprah Winfrey
"There is still no resolution and there has been nothing concrete on the cause of [Whitney's] death, and they were hoping for that," a Houston family friend tells PEOPLE. "There were members of the family who weren't keen on [the interview] going down at this time."
The insider says some of Whitney's close relatives wanted her to hold off on speaking publicly this close to her mother's death
. "There are people who just want her to stay out of the limelight for a while," says the friend. "This is a little girl who just needs some time."
The next step for Bobbi Kristina – who currently is spending time with her aunt Patricia Houston and Whitney's brother Gary Houston – is up in the air.
"She's so very young and impressionable," says the source. "She has to start finding herself as a woman on her own as opposed to defining herself as Whitney's daughter and Whitney's support. It's kind of interesting to see what's going to happen to her from here on in."
The source, who says Bobbi Kristina "has definitely wanted to walk in her parents' footsteps," and pursue singing and acting
, would have a tough act to follow. The source explains that "she will always have to deal with the constant comparison. I think she needs to find her own niche."
Bobbi Kristina's interview, which also features Winfrey's interviews with Patricia and Gary Houston, airs Sunday, March 11 on OWN's Oprah's Next Chapter