Amy Compston heads toward the finish line at Monday's Boston Marathon. She completed her fourth in a time of 3:34, good enough to qualify for the 2017 race. SUBMITTED PHOTO

Amy Compston heads toward the finish line at Monday’s Boston Marathon. She completed her fourth in a time of 3:34, good enough to qualify for the 2017 race.

BOSTON — Amy Compston knows this much: It was not be her own might that she made a qualifying time for the 2017 Boston Marathon.

Compston, running on a gimpy leg that has plagued her for months, turned in a time of 3 hours and 34 minutes on a sun-splashed day in Monday’s 120th Boston Marathon.

“God’s grace was all over it,” she said. “My leg didn’t hurt at all. I was so surprised I could hold out.”

Compston, who was competing in her fourth consecutive Boston Marathon, desired to have the chance to make it five in a row and for that to happen her time had to be 3:35 or less.

“It was only by God’s grace that I qualified. There’s no earthly reason why I would. I ran the least amount of miles ever preparing for a marathon because of the leg injury. Even last week it was bothering me where I had to stop and stretch it out.”

Compston’s IT band has been hampering her since last November after completing the 94-mile West Virginia Trilogy.

“God reassured me every day I was here (that she would qualify),” Compston said. “If I kept moving He said He would get me through and He did.”

Even during the difficult 23- and 24-mile stretch of the Boston Marathon, where many runners begin to fade, Compston said she reached down for a little extra.

The key was a steady pace, she said.

“I had to make myself slow down in the beginning. You’re excited and wanting to run. It all worked. I told Chris (her husband) surely I can maintain an 8:10 (pace). My ending pace was 8:10. I’ve never been so happy for a 3:34 in my life.”

Compston said she feared letting not only herself down but her family, who were already making plans to have a Boston Marathon reunion in 2017.

“My family will be do disappointed or depressed if they don’t let me in with that time,” she said.

Boston’s treacherous hills weren’t easy especially with the lack of preparation, she said.

“I hadn’t even run hills in the training. My leg couldn’t handle the hills. I knew I needed to be smart. I tried to do a few hills (in training) on my long runs but I didn’t do the hill runs — like running up and down Ashland Avenue — like I had in the past.”

But when the hills came she found her pace strong and even passed some runners.

The 70-degree temperature bothered a lot of the runners, she said. “There was a lot more walking this year than I can remember before.”

Compston said the security in the runner’s village was even more than the past three years. Mark Wahlberg was filming some for his movie “Patriot Day.” Chris was only a few feet from the set in the morning hours.

“I think Chris was more excited about that than anything else,” she said. “I’m glad he got to see it. He’s a big movie buff.”

Of course, Compston shared the Amy For Africa mission. She spoke with a woman on the bus ride to the start of the Boston Marathon. The Colorado woman was running her ninth Boston and told Amy she wanted to run for and donate to AFA after hearing the testimony.

“She was in tears by the time we got there,” Amy said. “She said it was her best bus ride ever.”