"I wanted to get into horses and learn how to ride," she told ABC News. And "I wanted to learn to train a dog to do something special. ... It was personal. It was a hobby. Horses and dogs."
So at the age of about 54, she started training dogs in disaster search.
"In a disaster, you know the confines of where a victim might be and that appealed to me," Melville said. "When there is a disaster, dogs look for people. They might be able to save lives."
It took four to five years for Melville to get the skills and train her first dog.
"Every day the learning curve was high," she said. "What I have learned along the way is that first there must be a commitment -- I mean an all-out, passionate and personal commitment. Perseverance is the key."
Today Melville heads the National Disaster Search Dog Foundation, which she started in 1996. The center, which is based in Ojai, Calif., trains dogs and firefighters in disaster search for free. The center is funded by donors, grants and donations.
She said that training the dog takes six months; the firefighter, about a year. The foundation, which Melville said was the "leader in the field of canine disaster search," has trained 131 teams -- 75 of those are now active.
Melville Worked During Oklahoma City Bombing
Her center also trained 40 percent of the canine search teams with the Federal Emergency Management Agency and 83 percent of the teams in California. These teams have searched for survivors during a wide range of disasters, including 9/11 and Hurricane Katrina.
Melville said that she would like to train 168 teams of dogs and handlers. The number represents those killed in the 1995 Oklahoma City bombing, in which Melville and her dog Murphy conducted search disaster.
"I had never seen evil so obvious," she said. "Never seen destruction of that nature. I have never seen people suffer. The beauty of the dogs is that they give people hope. They give people hope that someone may be found alive."
She said her foundation looks for shelter dogs with traits that don't fit easily into a normal family setting. Many of these dogs would be euthanized, she said, because they are tried in various homes but are returned because people don't know how to deal with the energy.
"It has drive. It is bold. It is able to focus," Melville said. "And it has energy. It wants a job. People don't normally recognize that this dog is a pearl. It needs an immense amount of training. Once that dog has training, it's able to focus and put its energy into the proper direction and [it] becomes a delightful dog."
"The rescued dogs become the rescuers," she said. "It's a beautiful sight to see a 60-pound untrained, difficult dog to deal with, and in six to eight months of training he has a purpose."
Melville said success was her driving force.
"To me, success is a fully functioning training center," she said. "Dogs need to have a sanctuary. Firefighter handlers need a place where they can come to be challenged to grow. This center is so needed nationally."
For those nearing or of retirement age, Melville shared these words of advice: "Get up. Go out. Look through a list of volunteer agencies and get busy. If you were here, I'd try to snag you to be a volunteer. At retirement you choose the life you want."
Tips for a Happy Second Act:
1. Get a mentor.
2. Take classes and keep learning, especially in the field you are entering.
3. Look for positive reinforcement from friends and family as you make the transition.
4. No shortcuts: Relish the chance to work your way up again and be confident in your abilities.
5. Keep moving: Physical activity is critical.