After missing a mammogram, Tina Knowles discusses her battle with breast cancer, saying, "I shudder to think what could have happened" (Exclusive)

 In this week's issue of PEOPLE, the mother of Beyoncé and Solange, who also writes "Matriarch," discusses her startling diagnosis and talks candidly about grief, love, and fame

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As she shares her personal story of breast cancer, Tina Knowles has a message of urgency for women everywhere.

 The superstar mother and author of the heartwarming new memoir Matriarch tells PEOPLE, "It's important not to slack on your mammograms," as she discusses her recent, life-altering health experience for the first time in this week's World's Most Beautiful issue.

 Knowles, 71, is the mother of Beyoncé, 43, and Solange, 38. She claims that last July, physicians caught her off guard when they found stage 1 breast cancer in her left breast.  She was finishing up Matriarch (available now wherever books are sold), and the news was announced shortly after she and Beyoncé debuted their Cécred hair care line.

I'm pretty private, so I wasn't sure if I would write about that voyage in the book.  However, I think there are many lessons for other women in it, therefore I chose to share it," she says.  Additionally, I believe that ladies can become overly preoccupied and rushed at times, but you need to go take your test.  Because I fear to think of what may have happened to me if I hadn't received my test early."

Actually, Knowles had neglected to get her planned mammography.  She claims, "I forgot that I didn't go to get my test two years before I thought I had," since Covid arrived and they contacted to cancel me, saying they would contact her when testing resumed.  I simply believed that I had done it.  Therefore, you can't tinker with that."

She describes how her daughters struggled with the news in Matriarch.  "I could already feel her mind racing, focusing on this as a task to tackle with precision," she says, adding that Beyoncé "took it well, staying positive."  "Mom, we are going to take care of this," Solange stated in the meanwhile.  She writes, "My girls became my team," with her niece Angie Beyince and bonus daughters Kelly Rowland by her side.

Knowles claims that no breast cancer genes were discovered in her and that there is no family history of the condition.  (Mathew Knowles, her ex-husband and the father of Beyoncé and Solange, has also successfully treated stage 1 breast cancer. He has stated that he has a mutation in the BRCA2 gene, which raises the risk of developing breast cancer and other malignancies.)

 Knowles had a breast reduction and surgery to remove the malignancy late last year.  "I'm doing fantastic," she declares.  "I'm cancer-free and extremely grateful that God let me discover it early."

In addition, women should be screened promptly ("I was unaware that there was a stage 0 screening").  "I want to show people you can go through that and still be fly," Knowles adds, adding, "I could have caught this at stage 0 if I hadn't missed my mammogram."

She claims that she is now "healthier, eating better, and I lost weight."

 Above all, the grandmother of four believes that she is a living example of what is possible.

 Knowles goes on, "I want to give people hope,"  "What scares me now is not making the best of every day that I have left in this life."