Academically, Kristina Hu, 16, is an early bloomer.

During eighth-grade at Longfellow Middle School, she scored a 2330 of 2400 on the SAT. That year, she self-taught herself calculus and scored a five of five on the Advanced Placement Calculus BC test, earning the teen her first college credit.

Kristina has matured from middle school to Thomas Jefferson High School for Science and Technology, the region’s governor’s school.

Entrance into TJ is highly competitive. Students, usually eighth-grade applicants, must complete an entrance exam, submit letters of recommendation and send transcripts to be considered for one of the about 480 freshman spots open at the school, which offers more rigorous math, science, technology and engineering classes than regular high schools.

This year, 3,410 students applied to TJ for the 2012-13 school year, up from 3,310 last year, according to the school system.

“I’m the first student in TJ history to take multivariable calculus my freshman year,” Kristina said. “It’s a senior-level class. I guess at normal high schools, it would be a college-level class.

“I came into high school with almost enough math credits to graduate.”

For that reason, Kristina chose to skip junior year and graduate a year early.

“I didn’t actually plan to graduate early from TJ when I came here. I actually decided my sophomore year when I sat down with my [guidance] counselor to sign up for classes,” Kristina said. “We realized that at the rate I was going, I would run out of math classes my junior year.”

Only about three or four students at TJ graduate early each year, according to the school.

“Graduating a year early from TJ, Kristina is a rarity even among her elite peers,” said school counselor Tonya Lathom, who is Kristina’s adviser. “Kristina truly is a unique young woman with an unparalleled drive to absorb and master knowledge. However, she is also a young woman who loves to shop; hang out and gossip with friends; listen, play, write music; and actually gives the best advice about how to deal with stress and the pressures of TJ.”

Principal Evan Glazer said: “Without question, graduating early from TJ implies Kristina is very dedicated to her academics year-round. When most students have taken breaks for vacation, Kristina kept focused on her coursework. … Without a doubt, she hasn’t taken any shortcuts in her efforts.”

Kristina said she initially had some reservations about graduating early.

“There are definitely some things, growing up with a class and moving up with that class, that I miss,” she said. “I’m formally in the Class of 2013, and now I’m in 2012.”

But she said if she wished to continue challenging herself academically, heading to college was a must.

“Skipping a grade is not for everybody,” said Kelley Hu, Kristina’s father. “Each child is different. Academics are one thing, social ability is another.”

Hu said he and Kristina’s mother, Patricia Xia, had no concerns about their daughter graduating early.

“When we agreed that she skip a grade at TJ, the main reason was not because she could finish her academic work one year early; it was because we knew that she was very independent, very mature, very capable socially and emotionally and more than ready for a college life,” he said. “Since she was a toddler, we started to encourage her to read, count and watch educational TV programs. … She could read simple user manuals and had a second-grade math level when she was in her kindergarten year.”

Around fifth grade, Hu said they began to realize Kristina had a special talent for learning.

“She attended [a gifted and talented] center at Haycock Elementary School. The math curriculum was too simple. She was bored,” he said.

The school system’s math instruction office tested Kristina’s skills, and it was decided she would attend Longfellow Middle School every morning for algebra classes.

Hu said that although his family does emphasize education — he has a doctorate in physics and Kristina’s mother a doctorate in electrical engineering — the family is pretty average.

“If you ask Kristina what she thinks about her parents, she would definitely tell you that we are typical American parents,” Hu said.

Kristina maintains a 4.41 GPA at TJ and will leave high school with 13 credits toward college.

“If anyone should graduate early, it’s Kristina,” TJ math teacher Jonathan Osborn said.

Although Kristina has advanced academically at a meteoric rate, Osborn said she is basically a normal girl.

“She definitely does not fit any of the stereotypes common culture loves to attribute to stars in math and science,” he said. “I think she’s an excellent role model for other young women in high school who are interested in mathematics or science, but may be afraid that these interests will interfere with their social lives. This happens at TJ just like it happens at other schools, and Kristina has managed to integrate her interests with her social life in a manner that is beneficial to both.”

Kristina has received early acceptance to Harvard University for fall; however, she is waiting to hear from other universities such as the Massachusetts Institute of Technology before making her decision.