Nina Fitzgerald is on an airplane bound for Alaska today to complete something she started in 2004: a career change at age 50.

It almost didn't happen because of Calculus II and other obstacles she dodged along the winding way. First, a little background.

In 2004 she was working in Utah as a registered nurse, "making a respectable living," but burnt out after nearly 20 years. She had read one of my columns on career change that year, posted it on her refrigerator and set a goal to finish what she started 30 years before.

She wrote me in 2005: "I have started back to school to pursue a degree in geology and work for the National Park Service. At first I had all the excuses. It will cost a fortune! I'll be 58 by the time I'm done paying off school loans."

But nothing would stop her this time.

Every day she drove 100 miles round trip to classes, to her part-time home-health nursing job, then home where she cared for her ailing father.

She went through her retirement savings and sold her house. She came by part-time work-study jobs and wrote a freelance column about hiking and geology. She secured scholarships and took on student loans. She rented an apartment with her brother.

"I have never wanted anything so much in my life," she says.

She got straight A's in geology classes. After working "so awfully hard" and engaging a tutor to help her through Calculus II, just a semester away from graduating, she went into the final exam with a B-grade.

"I failed it with a miserable grade, and the teacher gave me a D-plus," she says. She needed a C to graduate. "I was so beaten down and thought that if I had to take that stupid class again that I would just fail again, so I just may as well quit and drop out."

Despite that blip, she rallied. She graduated in 2009 and worked at Cedar Breaks National Monument as a park guide for the summer.

Accepted into graduate school, she was offered a teaching assistantship at Northern Arizona University — despite the Calculus II grade — where they told her, "That's not all we look at." Her extensive undergraduate research, 3.9 grade-point average in geology classes and glowing recommendations from professors spoke volumes.

"I remembered one of my original goals was to work for the National Park Service as an interpreter in mainly mountainous parks in the western U.S.," she says. "So after much soul-searching, I declined the assistantship. I knew I had done the right thing."

Today at 57, Fitzgerald is headed to Alaska to begin her seasonal job as a GS-5 park ranger interpreter at Katmai National Park and Preserve, where the largest volcano in the 20th century erupted in 1912. She probably will work seasonally a few years before getting a permanent position.

"I will just have to see how it goes," she says, seeming comfortable with not knowing exactly how things will turn out.

For now, she will hike until mid-September, explaining to visitors the difference between metamorphic, igneous and sedimentary rocks and jabber on (her words) about mineralogy if someone wants to know more.

"The mountainous parks have by their very nature a geologic story to tell," she adds.

And so does Nina Fitzgerald. It's a story about someone who simply refused to accept her career might-have-beens and was determined to explore the what-could-bes. Check out her ongoing venture on her http://blog,geo-travels.blogspot.com.

Reach Andrea Kay at andrea@andreakay.com.