It was already 8 p.m. and Tiana had yet to call for our interview. The topic was bisexuality, or more specifically, her bisexuality. A junior in high school, Tiana recently came out to a few friends about her sexuality. Now, I was waiting for her to come out to me.

Most of Tiana's friends were either gay or lesbian, but Tiana never once considered herself in this category. For most of our high school years, she had been straight (or heterosexual) -- and even had a 3-year-old daughter. So when she came out, people didn't really believe her.

When I finally called Tiana at 9:30 p.m., I found her taking it all in stride. The comments that bothered her were those that proclaimed her "too pretty to be gay."

"Gay, lesbian, or bisexual doesn't have a face," she says. "I am a human being and that's all that matters."

Tiana didn't always feel this confident.

"At first," she confides, "I didn't consider myself lesbian or bisexual. I was straight."

She stuck to this belief until one day something happened to make her doubt it. "Someone told me that this girl had a crush on me," remembers Tiana. "At first, I was disgusted. But when I got to know her more, I liked her personality, the way she made me laugh and just her as a person."

This experience changed her forever. "From then on," she says, " I looked at females differently."

But Tiana also still likes guys. 

"I like the person for the person. What matters to me is their personality, how they make me feel and if I like them for them."

Some, though, wonder if girls like Tiana, who seem to be heterosexual for years and then come out, are just trying to be trendy.

"When I was a freshman, it was really cool to come out, says Micaela, 17, from Minnesota. "I knew people who said different things depending on who they were around. They said it so other people would think they were cool and accepting, basically so they could get noticed."

"It's a fad and it's experimentation," adds Monica, 16, from New Jersey. "It's a fad that's been accepted by the media. Just look at shows like Real World that almost glamorize being bisexual or lesbian."

Maybe some of the media do make bisexuality seem cool (which is a whole lot better than painting it as something to hate). But are some teen girls choosing bisexuality to be in? Or are they facing up to a secret they've hidden, even from themselves, all their lives?

"People don't choose their sexual orientation,'' says Brad Becker, co-founder of the Gay and Lesbian National Hotline in California. "They realize or come to understand their sexual orientation over time. Usually, a person's sexual orientation doesn't just change out of the blue. People are aware that they're attracted to the same (or opposite) sex long before they actually act on their feelings"

That's what happened to Andrea, 17.

"I used to imagine being with a woman, not just physically, but emotionally too," she says. "But I kept dating guys.

Her coming out process started on the Internet when she would visit gay chat rooms. "I realized I felt very comfortable with that," says Andrea.

She also felt comfortable hanging with other girls who were bisexual. "When I started chilling with them, it made me see that this is what I am," she says.

Others know from the time they're very young that they are gay.

"I never thought I was straight or bisexual. I always knew I was lesbian," says Monique. "As far as I can remember, I always felt this way, but it was hardest for me in grammar school because everyone was talking about boys and I couldn't feel the way they felt."

This led to confusion.

"I didn't understand why I was that way, she remembers. "I wanted to know why I felt like this."

But now, Monique is more comfortable with who she is. "I just don't like guys, and I won't try to change this. Because I won't ever try to lie to myself."

So, if you're feeling confused about your sexuality, how can you sort things out?

First of all, know that a lot of people have sexual feelings or experiences with people of the same gender and don't grow up to be gay. Other people date members of the opposite sex while they're young and do grow up to be gay.

What does that mean? Feelings often change over time. So, don't feel pressure to label yourself right now. Just try to realize how you feel toward different people and in different situations. Try to figure out what makes you happy.

"Being curious, confused or experimenting with your sexuality is normal," says Becker. "Eventually understanding your sexuality comes from understanding how strong your feelings are towards people of a certain sex and how long you have had these feelings. Don't even worry about figuring out whether you're gay, lesbian, or bisexual. Instead, see where your feelings lead you.''

And, above all, be honest with yourself.

If you're really confused or your feelings are bothering you, talk to your parents or another trusted adult (a school counselor, health teacher, relative or family friends are some possibilities). You can also call the National Gay and Lesbian Hotline at 1-888-843-4564.

National correspondents Caitlin O'Fallon, Minnesota, and Pauline Hemmingway, New York City, contributed to this story.