At 12 years old, Crystal Wellhausen is a cell phone expert.

Crystal, a junior high school student in Largo, Fla., has had her phone since she was 10, when her parents bought it for her so she could stay in touch at her karate tournaments. Now she regularly calls her friends, changes the ring tones and plays the game Brick Attack.

“It’s silver, and it’s, like, a Nokia,” Crystal said. “It has a frog on the cover of it as a screen saver, and it glows when you use it.”

The girls’ dream of having a conventional land-line phone in their bedroom is as out of date as black-and-white TV and record players. It has to be cellular. And it won’t wait for high school.

Cell phones now are essential accessories in middle school. One cellular company says research shows about 25 percent of kids age 10 to 14 have a cell phone. Two of every three who don’t have cell phones want one.

More and more junior high school students are using cell phones to call their friends, send text messages, vote for their favorite music videos and play electronic games.

Latrice Crook, 14, of St. Petersburg, Fla., uses her phone for downloading SpongeBob SquarePants messages and looking at music offerings on VH1 and MTV. Her phone also features a “rescue ring.”

“If you’re on a date and you don’t want to be there, it will call and you can make up a story,” said Latrice, a junior high school student who doesn’t date.

If she did, she’d schedule the ring to go off at a particular time, answer the phone and report, “My mom told me to come home.”

Cell phone companies have rolled out new prepaid phone plans and family plans, complete with several phones and a huge chunk of minutes, to attract young consumers. But parents usually pay the bills.

In a 2002 national survey, 30 percent of cell phone users said they had at least one child under age 18 who had a cell phone, an increase from 5 percent in 2000, according to the Yankee Group, a Boston-based research firm. Nearly 70 percent said they paid their children’s cell phone bill.

The number of younger teens using cell phones is expected to rise sharply in the next few years.

But some families are fighting the cell phone craze among junior high students students.

Michael Bracht, 11, of St. Petersburg, has been begging his parents for months to no avail. He recalled his parents’ words: “When you get a job and you pay your own bills, you can have a cell phone.”

The Yankee Group research found nearly 60 percent of parents listed “security and emergency purposes” as the primary reason for giving a cell phone to a child or teenager.

Sometimes, students flout the rules against using cell phones at school. While teachers are teaching, their students silently send text messages to one another. One dials a friend’s number, types in the word “Hey,” and sends it. Seconds later, the friend’s phone lights up.

Text messages ring up at about 10 cents a message, and downloading ring tones, another popular pastime, costs as much as $1 apiece.

Some children pay for their own phones.

Rashad Moore, 14, of St. Petersburg, bought his Nokia phone for $60 six months ago. He purchases a card for $20 or $30.

His cell phone serves as his electronic address book and part of his wardrobe. When he meets a girl at the mall, he punches her phone number into his cell phone. Girls may also notice that his cell phone matches what he is wearing. He has red, black, green and blue phone covers.

“If you got an all-black outfit on,” he said, “you put the black cover on.”