In the first Advanced Placement exams ever taken at home, many participants found the last minutes of the test to be the most unnerving. But Kara Shapiro, 16, and Jacob Swisher, 18, both of Washington-Liberty High School in Arlington, Va., said the first minutes bothered them more.

Shapiro, a junior, sat in her family’s first-floor sunroom and fretted as she waited for the AP U.S. History exam to load. It was 1:30 p.m. on May 15. She had woken at 11 a.m. and nourished herself with a peach-strawberry smoothie (with protein powder) and a banana. She was ready to go. The test was not scheduled to begin until 2 p.m.

Swisher, a senior, had the same problem: youthful impatience. He was at his desk in his upstairs bedroom on May 12 waiting, waiting, waiting for the 45-minute AP Calculus AB exam, also scheduled for 2 p.m. He had gotten up at 10 a.m., enjoyed the crunchy goodness of a toasted bagel with jelly, reached the test site at 1:30 p.m. and filled in his personal information. He had to wait 20 minutes for the first question. That, he said later, “was the most stressful part of the exam.”

An estimated 4,914,000 AP exams, just 4 percent less than last year, were given in 38 subjects this month in what have become the most-taken tests in America. AP and similar programs have raised learning standards in U.S. high schools to a level never seen before. College credit can be earned for good scores. The program has grown so motivating for students that when the College Board asked 18,000 AP enrollees if they still wanted to take the 2020 exams, 91 percent said yes.

Many students, in comments, begged to be allowed to take the difficult exam they had been studying for. They wanted at least one thing to go right during their worst spring ever. The College Board budget was close to balanced last year, but this year it expects to be significantly in the red, partly because of the technology, security tools, and other expenses required for this at-home testing, a one-time event. But its trustees were college and high school educators, not business executives, so they gave the kids what they wanted.

Because of that good deed, the trustees have been sued for more than $500 million, plus punitive damages, by several plaintiffs, including the National Center for Fair & Open Testing (FairTest). The College Board is accused of breach of contract, gross negligence, unjust enrichment and other offenses. The plaintiffs did not sue the other major college-level high school programs, International Baccalaureate and Cambridge International, even though they ignored student wishes and canceled their exams.

I asked Bob Schaeffer, interim executive director of FairTest, why AP students shouldn’t have been allowed to take the exams they asked for. “The students did not take the AP exams they (or their schools) had paid for,” he said. “Instead they were administered quickly cobbled together, skeletal versions of the standardized tests . . . delivered on a platform that was simply not ready for prime time.”

There have been many complaints from AP students who had trouble submitting their completed exams for grading. The College Board blamed the problem on small and usually innocent departures from testing requirements for devices and file types, not surprising when 3 million students are testing in a new way. It calculated that less than 1 percent of test takers failed to submit. It has scheduled retakes in June for students who need to try again. It has also created a way for test takers to turn in their work via email.

Shapiro and Swisher had no trouble submitting. During the test, Shapiro regularly checked the timer on her screen. As best she can recall, she spent the 45 minutes of the exam on a question, backed by four documents and a picture, asking her thoughts on the impact of U.S. political reform movements from 1877 to 1914.

Swisher survived his wait by watching an episode of “The Office.” He wouldn’t have had that option if the exam had been at school, the standard testing site in the previous 64 years of AP administrative history. He hid the timer on his screen. It was too stressful, and unnecessary, since there was a clock. He had two questions, each with many parts. One required he interpret a graph by finding critical values and points of inflection as well as evaluating certain integrals. He used a mechanical pencil to write his work on two pages from his calculus notebook, then sent his photographs of them via his phone.

Many teachers told me they hoped the retest and the email option would eventually reward their students’ hard work. Nadya Martinez, an AP Calculus AB teacher at the IDEA College Prep charter high school in Edinburg, Tex., said six of her 20 students weren’t able to submit. Martinez grew up in that Rio Grande Valley city, population 98,665. It is a community of faith. She is encouraging everyone to pray for a happy ending.

AP test takers this year were at least able to make themselves more comfortable than usual. Shapiro got a call just before the exam from her grandmother Rosemary in Lake Worth, Fla., wishing her luck. She wore a T-shirt from a favorite beach shop and Nike shorts. Swisher wore Under Armour shorts and a T-shirt commemorating the 2019 national basketball championship won by the University of Virginia, which he will attend in the fall. Neither wore shoes.

Their principal, Gregg Robertson, is retiring this year after producing one of the few diverse neighborhood high schools anywhere with nearly everyone taking AP or IB. He said he is happy that all AP teachers for the first time will receive copies of their students’ work.

College Board Senior Vice President Trevor Packer said veteran AP teachers and college professors will be grading the exams, as usual, but this time they’d do it from their homes rather than at big reading sessions in hotels around the country. He said AP could have designed a system that would have automatically accepted whatever students sent, but then the 15,000 graders would have received thousands of files they would not have been able to read.

Packer said the testing requirements were designed to prevent students from receiving unfortunate messages in July, after scoring was complete, telling them: “You sent us a file that the readers were unable to open. No score for you.” The June retest gives students a chance to try again on the 45-minute 2020 exams, much shorter than the three hours plus of previous AP tests, but shown in the past to reflect college-level learning.

Both Swisher and Shapiro said they hope to get 4s on their exams, the equivalent of a strong college B. Swisher could get course credit from U-Va. for that.

Next year, if nothing goes wrong, Shapiro will be taking AP Government, IB Biology and IB English. They will all have very long final exams, without the perks of testing at home, but also absent the uncertainties of being part of a national experiment.