Pattie Mallette and Justin Bieber
Since her son Justin Bieber
's 18th birthday
in 2012, Pattie Mallette has had to come to terms that he's a legal adult and allowed to make his own decisions and his own mistakes
"When your kids hit a certain age your parenting style changes and it is hard letting go," Mallette tells PEOPLE. "His life was my life and now I've had to let him go a little bit and let him be independent. It is hard to not be able to control everything that your adult child does."
Mallette, 37, finds it "difficult" to answer questions
about the pop star's recent controversial behavior
but continues to support her now 19-year-old son
from afar as he travels on his world tour
"Every parent worries," she says. "I text and call him every day. I definitely want to know everything that he is doing and what he is going through so I try to talk to him as much as he'll let me. I mean, he's on tour and being pulled in a million different directions but we talk as much as he is able."
At the same time, she has to strike a balance, giving him distance.
"A lot of people might think that I have my head in the sand or that I am oblivious to the things my son is doing," she says. "I know who my son is and I don't always agree with every single thing that he does but I don't necessarily have to address that with everyone else. He's my son and I have to respect he is not going to want me going around being 'that mom' talking about his behavior."
The questions have been frequent for Mallette, who is currently doing a press tour for the recently released teen edition of her New York Times
bestseller Nowhere but Up: The Story of Justin Bieber's Mom
"Regardless of how uncomfortable I get with some questions I am receiving I just remind myself right away why I am doing this." says Mallette, who has restructured her memoir to help teens tackle depression, bullying, and anxiety. "I just want to help make a difference."
And stepping more in to the spotlight has also given Mallette a fresh perspective on the scrutiny her son faces in Hollywood.
"I can appreciate even some of the pressures that I knew were there but I couldn't feel them. You don't know all the expectations and the things that are around him so I have a different view. I've learned from watching him and how he has been able to handle things," she says. "I'm not going to like every aspect of [doing press] but even if it has only been one person that I could help with my story then it is all worth it."