The angst has not subsided. At the age of 24 — which is close to geriatric status in figure-skating years — Ashley Wagner repeated last week that she sometimes still questions why she continues to skate.

The defending national champion went public with her doubts last month, after a horrific short program dropped her to last place at the Grand Prix Final. Training partner Adam Rippon talked her off the ledge that day, reminding Wagner to look beyond results. After rebounding with a gutsy free skate, she enters the U.S. championships with greater confidence — along with a greater sense of purpose, refined by pondering what she wants to accomplish before calling it a career.

Wagner's pursuit of a fourth national title begins Thursday with the women's short program at Xcel Energy Center. A victory would make her the oldest U.S. women's champion since Maribel Vinson in 1937 and put her on course for her ultimate goal: a medal at the world championships, two months from now in Boston.

She doesn't expect anything that happens this week to end her uncertainty about how much longer she wants to compete against her sport's constant flow of precocious teens. This week, when Wagner returns to the arena where she won her first senior nationals medal in 2008, she will put aside thoughts about the long term and concentrate squarely on the here and now.

"I think it's completely natural at this point to have those moments of doubt,'' said Wagner, who will turn 25 in May. "I feel like everywhere I look, there's a newer, fresher, younger skater who is coming up that is technically sound and practically undefeatable. For me, I'm always having to work that much harder to stay relevant, to stay in shape, to keep pushing the envelope.

"I do every now and then think, 'What am I doing here? This is never going to stop.' But I love the sport. I love a challenge. And I'm extremely stubborn.''

Wagner and 2014 champion Gracie Gold are expected to battle for the top two spots on the podium. After winning back-to-back titles in 2012 and 2013, Wagner dethroned Gold last year, beating her by more than 15 points to become the first woman since Michelle Kwan to win three U.S. championships.

Lead-up to nationals

A child of a military family who moved frequently during her youth, Wagner now trains in Los Angeles under coach Rafael Arutunian. She enters the nationals off a victory at Skate Canada and a pair of fourth-place finishes at NHK Trophy and the Grand Prix Final — where she was defeated by two skaters from Russia and one from Japan, all 17 or younger.

Her experience at the Grand Prix Final, Wagner said, convinced her she hasn't peaked yet. Following a shaky performance at the NHK Trophy, she faced the world's top skaters in the final in Barcelona and fell on a jump in the short program, putting her in last place. A phone call from Rippon helped clear her head, and she skated a lights-out program to music from "Moulin Rouge'' to finish third in the free skate with a personal-best score of 139.77 points.

"She was upset,'' said Rippon, among the favorites in the men's competition that begins Friday. "She didn't know why she was there or what she was doing.

"I told her if she was proud of her skate, she would be proud of herself, no matter what the result was. We both remind each other of that. The results have to be secondary, but they will come if we focus on our personal improvement and our personal goals.''

Wagner missed the bronze medal by only 1.32 points but lamented her inability to put together two clean, solid programs. Her training since the Grand Prix Final has centered on consistency, and she said she is "on a mission'' to become a more complete skater.

'Pushing my limits'

She and Arutunian went to Colorado Springs to allow her to prepare for the U.S. championships at altitude, in a highly focused environment. Though Wagner is known for her ability to rally from poor short programs, she said one of her goals at nationals is to skate a spot-on short and maintain her drive and concentration through the free skate. Arutunian has made her technique more efficient, Wagner said, and her willingness to listen to him and follow his instructions have allowed her to continue improving even at a relatively advanced age.

"When I go out and I am skating my best this season, I'm getting personal best [scores],'' Wagner said. "I'm pushing my limits, so I know I'm capable of much, much more. The challenge for me is just getting to that point where I can go out and put out those programs. That's something Raf and I have worked on.''

Last year, Wagner said, she recaptured her U.S. title because she had a sound strategy and followed it to the letter. She feels just as thoroughly prepared this time around, with the world championship on her mind as well.

A victory would guarantee Wagner a spot at worlds for the sixth time. She never has finished higher than fourth, as the Americans remain in a sustained medal drought at the event.

At the Grand Prix Final, Wagner said she was tired of saying "tomorrow is another day.'' With fewer tomorrows remaining in her career, she feels what she called "a whole new type of pressure'' to make every one of them count, removing any doubts about how great she can be.

"I really don't think any other top lady has improved as much technically as I have at my age,'' she said. "That is something rare, and definitely something I'm proud of. Skating is what I put my heart and soul into.

"After the Grand Prix Final, I realized it's not about questioning what I'm doing here, but just focusing on the fact that I'm here. I've said I want to be here. Now I need to skate like I want to be here.''