Playtime Is Not Yet Over for the Boys of Immature : Pop Beat: The teens’ hit ballad ‘Never Lie’ invites comparisons to the Jackson 5. But many other kiddie groups end up in the has-been bin.

The 13-year-old boys in Immature, the Los Angeles R&B; vocal group whose soulful “Never Lie” is one of the fall’s biggest singles, seem determined to live up to their name as they gather to discuss their suddenly escalating career. The youngsters’ nicknames are Batman, Romeo and LDB, but you could easily substitute Larry, Moe and Curly.

In their manager’s North Hollywood office, Marques (Batman) Houston, Jerome (Romeo) Jones and Kelton (LDB) Kessee--can’t sit still very long.

Crammed on a small couch and constantly jockeying for more comfortable position, they squirm, poke each other, giggle, trade insults and constantly interrupt each other.

They do one have serene moment--crooning an a cappella version of their hit ballad. After finishing, Houston boasts: “I told you we were good.”

Since the group started getting airplay last summer, there has been an endless series of comparisons to the Jackson 5. That may be a stretch. How many times does Michael Jackson come along in a century?

Still, these guys are far better than most pubescent singing groups, most of whom have lots of attitude and flash but scant talent. Immature can not only carry a tune and harmonize effectively, they can also play instruments--Jones on bass, Houston on keyboards and Kessee on drums.

For a kiddie soul collection, the trio’s “Playtyme Is Over” is solid stuff.

“People think we’re too young to be good singers, but we fool them all the time,” Kessee says in a serious moment. “We’re young, but we’ve had a lot of experience.”

Though barely at puberty, these teen-agers already have made two albums and been on two different labels. They were signed in 1991 by Virgin Records, but were dropped after their 1992 album, “On Our Worst Behavior,” flopped.

To hear the group tell it, the failure was no surprise. Even they didn’t like it.

“That album was too bubblegum,” Jones says, sliding off the couch onto the floor. “It was just for kids. Our image was for kids too . . . weird clothes, a bright, colorful look. But a lot of people weren’t relating to the look or the record.”

Reclaiming his spot on the couch, Jones continues: “The new album is less bubblegum, something kids and adults can relate to. It’s not immature, it’s more mature.”

Immature got started about four years ago when Jones, who was born in Venice, and his manager, Chris Stokes, were looking to start a group. They recruited Houston, who appeared on the first album, and ultimately Kessee, who joined after that album was recorded. Both are from South-Central Los Angeles.

“We all have always wanted to be in show business in some way,” Jones says. “We’re natural performers, I guess.”

*

If the music career doesn’t work out, all have acting experience to fall back on. They appeared in the movie “House Party 3” and the last few episodes of the TV show “A Different World.” Houston is the most experienced actor of the group, with a regular role as a pesky neighbor on the ABC sitcom “Sister Sister.”

Highly rated during a trial run this past spring and summer, the show is scheduled to return at the end of this year as a replacement for one of the new season failures, a show spokesperson said.

The demands of a hit series, though, could cause conflicts with Immature’s singing career. If faced with the choice of TV series or Immature, Houston insists, “I’d stick with my boys.”

He looks serious and sincere until Kessee declares, “I don’t believe that.”

The trio trades insults for a short while before winding into a discussion of what’s clearly their favorite subject--girls.

“I love the idea of girls screaming over me,” Houston gushes. “It makes me feel great. I hope that part never ends.”

But that part, as well as their music career, faces familiar obstacles. Most singers geared to the fickle kiddie market are has-beens after a few albums. Even New Kids on the Block--one of the biggest sellers of the last decade--have been placed in the has-been hall of fame by most pop observers. And don’t forget all the talk about big careers for such other fading hit-makers as Kris Kross and ABC.

The youngsters, however, appear to be confident.

“As far ahead as I can see, we’re doing very well, selling million of albums, going on tours, with girls screaming and crying,” Houston boasts.

Should they last for several more years, that name Immature won’t fit.

“We’ve thought of that,” Houston says. “We’ll just change it to I’m Mature. We’ll be mature by then.”

“Don’t bet on it,” Jones quips.