I’m 24 and looking for a job. As I sit in another lobby waiting for today’s interview to begin, my BlackBerry chirps with my daily email notification matching my résumé with potential employers. “Based on your qualifications, we recommend these openings.”

One of my qualifications: until June, I was working at a school in Oak Cliff as part of Teach for America, the national nonprofit organization that enlists recent college graduates (like me) to teach in low-income communities for two years. Teach for America launched in Dallas in 2009, and I was part of its inaugural group of teachers. Many stayed. I left.

I scroll down hoping today is the day I find the job for which I’ve been looking. Truck driver, court reporter, border patrol officer, and a lactation consultant. Great professions in their own right, don’t get me wrong, but not exactly the doors my Teach for America recruiter told me would swing open with TFA on my résumé.

Part of what attracted me to TFA was the prestige, the potential to one day work for a prominent employer. Sure, I care about helping those less fortunate than I, as does any human with a soul. You’ve got to sweeten the pot a little, however, if you want to systematically recruit high-achieving individuals to a systematically underperforming public education system. But that’s for another discussion.

“Hi, you must be Caitlin. Come on in.”

My hands are sweating like mad. Thank God I remembered to put on my Drysol last night. The thought of talking to one middle-aged professional about how I could be the perfect employee makes my heart race as if I’ve been doing cardio for an hour. I am ashamed of my anxiety. Why am I so nervous? For two years, I stood in front of seventh graders, talking for hours on end as their eyes burned through me. For two years, I fielded their funny, inappropriate, and brilliant questions. I had a ramrod straight backbone then. An interview with one person should be easy. But I bombed last week’s interview, and who knows how this one will go.

“So tell me a little about yourself.”

I was born in ... moved to ... graduated from ... completed internships with ... and then I joined Teach for America.

I’m all too familiar with the two reactions I get at the mention of TFA: the furrowed brow that comes from unfamiliarity with the program or the eyes-wide-mouth-slightly-agape-slow-head-nod move that means he or she has heard the Dallas ISD statistics and finds my work admirable. Either way, the interviewer has no idea what really went on in my classroom, and the interview inevitably becomes a one-woman rambling session as I struggle to find the right words.

“So what did you do in this Teach for—what’s it called?”

What goes on in a classroom is, by and large, a mystery to outsiders. Each day was a circus, and I tried to be the ringmaster. I had things planned and backup plans for my backup plans. To the bystander, of course, Portable 24 probably looked like a madhouse some days. Trying to get a 13-year-old to verbalize the thematic lesson he or she most connected with in The House on Mango Street (a high-level novel that addresses racism, sexism, and abuse) is like a trapeze act: scary, dangerous, and exhilarating. I was the audience cheering them on, and I was the safety net there to catch them if they fell. And some kids would probably equate me with the evil circus owner, forcing them against their will to—gasp—read a book.

My students learned a lot in my classroom. Dallas ISD will tell you 83 percent of my students passed their Reading TAKS test my first year, and 92 percent passed in my second year (both numbers exceeded the district average.) But I struggle to explain success beyond quantitative measures. They achieved so much more than numbers on a piece of paper. I had girls who once idolized Teen Mom asking me about college. I had boys who weren’t allowed to do homework or carry backpacks as part of their gang’s initiation begging me to keep their library books safe. How do I explain all this without sounding like just another teacher-saves-the-day cliche?

So I opt to keep it simple and talk about students’ academic and life trajectories and closing the achievement gap. It sounds so anticlimactic coming out of my mouth that I want to vomit.

“Describe an obstacle you had to overcome in a job.”

I’ve prepared for this question, coming up with a million examples. For me, though, words don’t come to mind. Faces do. Faces so vivid I feel like I’m right back in the classroom. My roster of more than 200 students during the course of two years floods my brain, and I remember all that I have left behind. The student who didn’t have running water in his house. The student whose father told me his son was going to drop out in eighth grade. The student who displayed pictures of her newborn baby in the clear plastic cover of her binder. Whatever the case may have been, each student came to my class deserving a quality education, and I did my damned best for two years to show them the power of knowledge. And now I’m leaving.

For the inaugural TFA Dallas corps, I am in the minority. Fifty-seven of the original 91 teachers returned to the classroom for a third year this past August. Their dedication is inspiring, and I feel honored to have called them colleagues. But I’m not them. Why am I leaving? “To explore other career opportunities” and “to advance in other leadership roles,” two of the standard responses I’ve tried practicing in the mirror before. They fail to fully describe my decision to leave.

I’m tired. Really, really tired. For two years, I devoted nearly every waking moment to my students. When I wasn’t at school, I was thinking about school. I was perpetually on the edge of an anxiety attack as the to-do lists pressed down on me like 1,000-pound weights. I put relationships with family on the back burner and became a distant memory to friends I once talked to daily. My life was consumed by the many hats Ms. Myers wore: educator, mentor, de facto parent, office manager, and DIY classroom renovator. But I won’t say that teaching was a burden, and I don’t want it to come across that way. I did for two years what many heroic people do for a lifetime. I’m afraid to say it, but maybe I’m just too selfish to continue.

The librarian at my school, a woman whom students and teachers alike fear, looked at me hard on the last day of school and asked if I was coming back next year. I had managed to dodge that question gracefully until that point. But then it was just me and her in an empty library, and her glare made me confess. “You are so young, so hopeful,” she said. “You have your entire life ahead of you and the ability to do whatever you want right now. So go. Everyone here wants you to stay, but it’s your time to go. We’ll always be here if you want to come back.”

Her words stung me, and I realized in that moment that she was telling me exactly what I had discussed with my students when reading The House on Mango Street. The book is a coming-of-age story of a young Latina girl who wants to escape her impoverished upbringing. She also wants to help her friends and family who are trapped in destructive cycles, which carries the threat of trapping her as well. Many of my students identified with the female heroine, Esperanza.