You are 13 and 30 pounds overweight.

Your parents have just divorced. Your mother has moved you and your four brothers from Florida to the family’s homestead in Alabama.

In this new space, your brothers have to share a room, but on the upside, you get your own. Yet the walls of your room are bland and there’s little more in there than a mattress and a box spring. You have your extended family surrounding you, but not a lot of friends. The girls at school are mean. You are inconsolable.

This was Phoebe Howard’s life 40 years ago, a series of days to endure until the moment an aunt stepped in with a bit of paint and fabric and transformed Howard’s bedroom into a delight of soft blue walls, floral fabrics and order. It was a simple act, but one that Howard looks back on as a turning point that set her on the path to becoming one of the nation’s most sought after and respected interior decorators.

“I had no idea she was doing it,” Howard said, as she closed her eyes and for a moment stepped back in time into that little blue room. “I came home and it was done. It was just perfect. And for a 13-year-old girl, it gave me just what I needed.”

And now Howard, who divides her time between Atlanta and Jacksonville, wants to bring that same joy to other young girls who can’t afford to transform their bedrooms. She’s also sharing her eye for interior design in a new book, “The Joy of Decorating: Southern Style With Mrs. Howard” (Stewart, Tabori & Chang, $50).

If the mantra against abusing your body with junk food is “garbage in, garbage out,” then for Howard it’s “if you live in a mess, then your life’s going to be a mess.” Throughout the pages of her new book the antidote to that message is clear. The rooms she creates are not some trendy, overzealous adaptation of feng shui principles. True, they are measured, ordered and controlled, but they are also elegant, inviting, soft and, like her childhood bedroom, pretty.

“People don’t understand that your environment ... affects your feelings,” Howard said. “When you open your eyes in the morning and you see something pretty, it’s going to start your day off right.”

Even after the transformative moment with her aunt, Howard did not immediately pursue interior design. She did not receive a degree in it or get formal training, per se. She was, however, surrounded by creative people: Her mother was an artist and art teacher, her father wrote for a newspaper. And when she married, she married a designer who’d studied at the prestigious Parsons the New School for Design in New York.

Still, she remained a stay-at-home mom until she was 38, when she and her husband, Jim, opened a furniture store in Jacksonville. In large part, she taught herself how to make a room functional and attractive by working and reworking store displays.

Now, the couple has shops in Jacksonville, Atlanta and Charlotte and their work is regularly featured in shelter and lifestyle magazines, including House Beautiful and Southern Living. Based on her softly traditional style that owes a debt to a classic Southern aesthetic, Southern Living recently tapped Howard to write a regular column in which she tackles design problems the average homeowner faces.

“I go to her for my own decorating dilemmas,” said Lindsay Bierman, the magazine’s editor. “She does something very few have been able to do, which is make high-end style accessible. Everything is curated, but in an inspiring way. It’s light, airy, timeless.”

Howard is the first to acknowledge that she’s had a charmed career, catering almost exclusively to wealthy clients with money to spend. That will not change. But this year the Howards will launch a furniture line that will be within reach of people who make less than six or seven figures.

Still, Howard cannot forget the lesson taught to her by her aunt Myra Thompson all those years ago. Through her blog, she launched a national campaign several months ago to find a 13-year-old girl who was in need of a room redo, just as she once was. Howard would foot the bill for everything, but the girl had to be truly in need, not simply have the desire.

Eventually, she wants to start a charity serving other 13-year-old girls who are at a rough spot in life.

“It’s a bad time in every girl’s life, because things are bad at school, your hormones are out of whack, you’re becoming a woman,” Howard said.

A friend of Lynn Hunter’s entered Hunter’s daughter, Amanda, into the contest. Amanda has cerebral palsy and will have surgery next month to put rods in her back so that she can finally sit up straight. Her parents are divorced.

Howard chose her out of hundreds.

“I was actually in tears when I found out Amanda had been chosen,” said Lynn Hunter, of St. Augustine, Fla. “This is really going to make Amanda feel comfortable and happy.”

The room is slated to be finished by the time Amanda is recovering from her surgery. At her request, the room will be done in purple, though Howard is trying to edge it gently toward soft shades of lilac.

“I know this room will be a game changer for her,” Howard said.

--------------------

Book Signing

Phoebe Howard signs copies of “The Joy of Decorating: Southern Style With Mrs. Howard.”

5-7 p.m. Wednesday. Mrs. Howard store, 425 Peachtree Hills Ave., Atlanta. 404-816-3830; www.mrshowardpersonal shopper.com, www.phoebe howard.net.