When Debbie Porterfield and Steve Stanford met five years ago in a crowded government class in Alexandria's Minnie Howard Junior High School, neither imagined that their almost instantaneous friendship would grow, as it did, into so delicate and wonderous a thing as first love.

But it did.

"We're in love," Stanford says as he and Porterfield sit, his hand gently laced into hers, in a conference room in the library at Alexandria's T.C. Williams High School, where the two are seniors and less than a week away from graduation.

"I just imagine us as always being together, close," Porterfield adds.

Both are 17. Both are from middle-class families. Both are college bound--he to Stanford University in California to major in electrical engineering and she to Harvard University in Massachusetts to major in biology. And both say that they realize their long-awaited high school graduation will mark the beginning of a new phase in their relationship, perhaps even its end.

But they say they are not discouraged. "We can do it," says a determined Stanford.

For thousands of high school sweethearts across the country, graduation day often is, as it has been for generations, a bittersweet moment of truth that will either test the strength of young love or provide an easy way to dissolve adolescent partnerships not meant for adulthood.

Porterfield and Stanford, who were recently named by their classmates as the "Most Intelligent" male and female in the class, have spent much time discussing the direction their lives should take after high school. Education and career must come before matters of the heart, which is why they decided to attend different schools.

"If we went to the same school, we would want to eat together, and study together," explains Porterfield. She says such isolation would prevent them from taking part in campus life.

Stanford says he even turned down Massachusetts Institute of Technology, where he would have minutes away from Harvard, in order to keep their resolve. Both say they did not want to influence the other's college choice.

Jimmi Barnwell, a senior counselor at T.C. Williams, says the couple's career-before-romance attitude is not surprising. Many students these days are career-oriented and less prone to emotional impulse, she says.

"They have goals and directions," she says. "And they won't allow anything to interfere with them."

That's particularly true for high achievers, Barnwell adds. Porterfield is valedictorian of a senior class of 755 and a National Merit Scholar. Stanford, also a Merit Scholar, was named by his fellow students as the student "Most Likely to Succeed."

"I'm the luckiest girl in the school," Porterfield says, tightening her grasp of Stanford's hand. "No other boyfriend treats his woman so nicely. I have a zillon flowers pressed in my dictionary."

"And she can read my thoughts," Stanford adds.

Lots of teen-agers may say they are in love, but Stanford and Porterfield say they actually mean it. "We're just not going to be stupid about it," Porterfield says. "It's silly to say that, 'Oh, I guess I will write three times a week and call every Thursday,' and think that will be the secret of staying together."

"They are just two kids who can't stand to be apart from each other," says Steve's mother, Pat. "I remember the relationships I had in high school. You think you are going to die if you can't be with that special person. But if the relationship they have is meant to be, it's not going to matter where they go to school."

Debbie's father, Jovan Porterfield, says he expects a lot of expensive "long-distance hand-holding" between Steve and Debbie when they start college, though the couple seems determined to be pragmatic and optimistic about the parting.

"It doesn't make sense to count the days and try to say we have to do this and this before we go," Porterfield says. "The point is that there is no reason to be sad now because we are going to be sad later."