(CNN) -- Sam Lamott, the baby star of best-selling author Anne Lamott's classic memoir, "Operating Instructions," was finally grown up and safely ensconced at art school in San Francisco.
Before Sam was born and during his childhood, Anne Lamott had developed a community of family and friends who had known and loved them during the lean years. She had written several notable novels and works of nonfiction. Now that Sam had moved out, Anne Lamott had the rest of her life to live. Surrounded by the love of her community, she had a wonderful home in Northern California with room for guests and dogs and an interesting professional and personal life.
One day before Lamott's Thanksgiving dinner for 25, she got the call. Sam, only 19, told her that his girlfriend was pregnant. Or was it his ex-girlfriend? Sam and Amy had broken up a couple months earlier but clearly had continued to spend time together. They were keeping the baby.
Jax Jesse Lamott was born on July 20, 2009.
Lamott, who turns 58 on Tuesday, had famously recounted her first year with Sam in a memoir that validated all the joy and agony and terror foisted upon her during her child's first year, made more challenging by the absence of the would-be father.
In a new memoir, "Some Assembly Required: A Journal of My Son's First Son," Lamott (with Sam's help) recounts her surprise and acceptance at becoming a grandmother earlier than expected, her fears related to Sam and Amy becoming parents at such a young age and her daily celebration of her grandson's life. The book will debut Sunday on The New York Times best-sellers list.
"I was happy all the time at the thought of Sam's being a father, and my getting to be a grandmother, except when I was sick with fears about their future, enraged that they had gotten themselves pregnant so young or in a swivet of trying to control their every move, not to mention every aspect of their futures," she wrote.
In a conversation with CNN.com, Lamott described her ongoing challenge -- a classic dilemma of the grandparent -- to contain her overwhelming need to advise Sam and Amy on every aspect of her grandson's young life.
CNN: What was your fantasy of life as a grandmother?
Anne Lamott: It would be 10 years later. Sam would be 29 and be the right age, young enough to have energy but old enough to have a fully formed cortex. He would only work four days per week because he would be so successful. I'd be really close to his wife. They'd come over, and we'd hang out. Or it would be horrible. They'd live 1,000 miles away, and I'd fly there all the time. I'd be 65. Everybody would be settled and successful.
CNN: What were your fears given how young Sam and Amy are?
Lamott: I was very calm when Sam first told me, but I'm one of those religious people who are afraid of everything. I'm instantly worried about everything that could go wrong. I thought, "It's all over, it's hopeless. He's going to drop out of school, work as a janitor and live with me."
I feared Amy would move, that the financial strain would be enormous, that Sam wouldn't stand up and do the right thing and that he would drop out of school. It's the familiar story of young people dropping out of school and getting dead-end jobs. I had every scary thought.
No matter what circumstances, it's hard to be a parent and maintain a sense of self and identity in the world. I don't have any romantic views of parenting. Every step of the way it's really hard. It's a dangerous world, physically and psychologically.
CNN: How do you stop yourself from trying to control their lives?
Lamott: I knew I'm a control freak and that I would want to manage their lives and be the third parent. I had to be very strict with myself and get help for my issues all the time. I could not say this was my kid, too. I would stop and say, "Wait, why am I talking?" Another woman, who had a grandkid when her daughter was young, told me, "It's their dishes and their sink."
It's intrusive for grandparents to think they're in charge. It's manipulative. Also, it's self-destructive, since if the parents have to resist you, you won't get your mitts on the kid as often. Once they don't have to resist you, they want to be around you. I was the one with the credit card and the washer dryer. If I didn't crowd them and show up with my clip board, they'd call or come over and do laundry.
CNN: Sometimes you have to speak up! What questions do you ask yourself before interfering?
Lamott: Because I'm helping Sam and Jax financially, I'm bearing the bulk of the financial responsibility. I try to ask myself, "Who says this is my business? Does this have my name on it?" If something is urgent, my experience says it's probably not God talking. It's usually my self will and low-level hysteria. If there's any way I can postpone saying it, it dampens the urgency. Then I can probably talk to a friend.
Left to my own devices, my first inclination is to mess in other people's lives. I secretly believe my whole family, and really the whole world, is my responsibility. But over the years, I've learned I can release people to their own destiny, and do the work that's ahead of me: writing for certain number of hours every day, teaching, church, friendships of 25 years, my dogs, our walks.
CNN: What is a grandma's job?
Lamott: My job of grandma is to keep the house safe for when Jax comes over. He and Sam usually come over on weekends, and I visit Tuesdays at Sam's apartment. I take up the slack. I'm the outdoorsy one who convinces everyone to take walks with me for owl prowls, not that we have ever seen an owl. I'm the chief librarian. There have been hard days since Jax was born, and it's also been the greatest blessing of my life.
CNN: Now that Sam and Amy have split up, how does a grandma handle the breakup?
Lamott: It's sort of the same thing. I have excellent ideas about how things should proceed now. I pray to God to keep one hand around my shoulder and one hand on my mouth. If anyone asks my advice, I give it to them.
I'm trying not to manage their lives or custody decisions. It's between the two parents, who get to make 100% of the decisions. Sam recommends that if you've got a problem, go work it out in the mirror. I'll ask myself, "What's going on? What's this really about?"
CNN: When Jax wants to run away from his supremely embarrassing parents, will he run to you?
Lamott: All parents are an embarrassment to their kids. Often grandparents are the relief. Kids don't have to resist you.
I've had the blessing of being someone that kids really love, so a number of kids have run away to me over the years. I always feed them, make them a cup of tea and take them for a walk. I'll do the same with Jax if the time ever comes. Then I'll sneak to the bathroom and call Amy or Sam on my cell.