"Before starting actual college work, I'd like to kind of go off and learn more hands-on," he said. He hopes to work with children and to volunteer at an orphanage. He won't get his specific assignment until he arrives.
Princeton's program, launched in 2009, is a formalized take on what has become known as the gap year: spending a year exploring interests between life stages.
Flexible gap years afford students a chance to learn about themselves and their passions, said Holly Bull, president of the Center for Interim Programs, which offers counseling to customize gap-year experiences.
The "well of time" known as a gap year allows students to step away from academics and become "fired up" about things they care about, Bull said.
John Luria, director of the Bridge Year program, said Princeton's program underscores academic integration more than a typical gap year. The university plans to examine participants' academic success as more of them complete their undergraduate courses, he said.
Advocates of general gap years suggest those who take them do better when they arrive on campus.
Robert Clagett, former admissions counselor at Middlebury (Vt.) College, examined gap-year students' academic success for the Classes of 2011 through 2014, and took into account factors such as high school rigor and curriculum. On average, he said, they performed better than they were expected to, earning a college grade-point average of between 0.12 and 0.18 higher than anticipated.
Clagett, who was on sabbatical this year and will start a new job at a secondary school in Texas, said he had sent requests to replicate the study at several other universities.
Some colleges, like Harvard, promote a gap year as a way for students to avoid becoming burned out.
Rotblat's mother, Gail, said she hoped Princeton's program allowed her son to "come back refreshed and really excited about going into a classroom" after years of working hard just to get to college.
In high school, he earned a 4.0 grade point average, was co-valedictorian with three others, and took part in numerous extracurricular activities, including bands and the National Honor Society.
High school can sometimes be a competitive pressure-cooker, he said, and he's now prepared to learn more through experience. He looks forward to seeing a new culture and music scene firsthand.
The scene in Rotblat's family room illustrated his transition: On one side of the room, boxes were being filled with supplies and essentials for his trip. Just feet away, Rotblat's trophies and certificates lined the top of a wall unit.
"A lot of incoming Princeton students, they're used to achieving in a very controlled environment," said Doug Wallack, 19, of Princeton Junction, N.J., who went to India last year through the Bridge Year program. In India, "those things were absent."
Wallack volunteered at a community library in Varanasi. He'll start his freshman year in September.
"Overall, I'll just go back to school not so emotionally invested in success, which is a nice thing," Wallack said.
In Senegal, the closest Rotblat will have to a classroom setting will be intensive lessons in French and two indigenous languages: Wolof and Pulaar.
Bridge Year participants do not receive college credit. Princeton funds the cost of the nine-month stays - which average about $30,000 per student - through alumni donations, and works with third-party organizations that help coordinate the trips.
Rotblat did volunteer work often growing up - stuffing envelopes at school during the summer and delivering charity baskets. He said the service aspect was a draw.
"Looking toward a future career, I never wanted to do a career because it pays a lot," said Rotblat, who is interested in working in education or with educational policy. "I don't have to personally benefit from it, but [if] it's benefiting other people, that's the greatest payoff."
This year, Bridge Year accepted seven students for each of the four countries: China, India, Peru, and Senegal. It was also the most competitive year, Luria said, with 94 applicants, up from last year's 59. In the past, only five students went to each location.
At first, Rotblat found the idea of delaying his freshman year odd, but, he said, he now doesn't "see any real drawbacks."
He learned about the program when a panel of past participants spoke at an "accepted students" day at Princeton. If he hadn't been selected, he said, he would have started his freshman year on schedule.
Eleanor Roberts, 20, of Cheltenham, who served a women's artisan group and microbusiness in Peru two years ago through the program, said, "It was really a smart decision because it helped me mature."
Roberts' career interest shifted from history to international development after the trip.
In Rotblat's sitting room, a Senegal guidebook rested on the family's coffee table, which is imprinted with a black navigational world map. Rotblat traced his finger across the table, demonstrating his travel plans from the United States to Senegal, which was not labeled on the map.
"Nowadays . . . the world's a much smaller place," said Rotblat's mother, a preschool teacher whose only trip outside the country has been to Canada. "It's going to be different for him than it was for me. If you have the opportunity to do it, do it."
Contact Angelo Fichera at 857-779-3814, firstname.lastname@example.org, or follow on Twitter @AJFichera.