Nineteen years old is a tough age. You’re not really a kid anymore, but definitely not an adult yet. You’re trying to grow up, but not too quickly. And you’re hoping that all your hard work now will pay off in the future.

Jack Christensen is 19. And he is growing up, too. The only difference between Christensen and the average teenager is that he is growing up on the road with his bass guitar strapped over his shoulder. He and his band, Scarlet Runner, are growing up in small bars with dim lighting. In front of crowds. In a van. On festival stages.

And Christensen wouldn’t change it for the world.

“I love life on the road,” he says. “I love to travel. I love to play. So combining the two things is a natural and enjoyable enterprise.”

The Waterloo-based blues rock trio also includes Christensen’s brother, lead singer and guitarist Jason Christensen and drummer Jeremy Ackley, who are both 22. They have undertaken an exhausting touring schedule, playing anywhere from huge festivals in Texas to tiny bars in Iowa. They’ve shared the stage with living legends such as Lynyrd Skynyrd, B.B. King, REO Speedwagon and ZZ Top.

Even the band’s time off is consumed by the business end of things, the younger Christensen says. In the past few months, Scarlet Runner shed its management and is handling band business on its own. The band has been booking shows, doing press and “spending lots of time on the phone,” he says. In fact, the band has been in contact with a few small indie labels about possibly getting signed.

“But that’s not the most important thing to us,” Christensen adds. “The most important thing is to play . but it is expensive to do things by yourself. It would be a big help if maybe we could find someone to help us do a single or an EP.”

But with all of this growth comes growing pains.

Recently, original drummer Luke Rathe parted ways with the band. Rathe had grown up too, but in other ways than his bandmates.

“We just had differences – and I wouldn’t say personal differences,” Christensen says. “He bought a house in the same little town we’ve grown up in, and he got married and got a job. He decided that working 60 hours a week was more important than making himself available to us . I think it’s pretty mutual that things weren’t working out with him at this stage of his life.”

Getting a new drummer was a major change for the band, who had been playing with Rathe since they were 13. However his departure paved the way for Ackley, the current drummer.

“He came and auditioned and worked out better than anyone else,” Christensen says. “We liked him right off the bat ,and we thought that his playing would fit us well. And it has.”

Even more fundamentally, the band’s sound has matured since their first album. On their latest album, “Departure” they’ve drifted away from their self-imposed blues borders and become more self-indulgent by going with their instincts and trusting their fresh ideas. Although the blues influence is still there, “we’re just letting ourselves through a little more,” Christensen says.

“I think a lot of what was on the first album, with the exception of a few songs, was us consciously trying to fit into a genre,” he says. “A month before we recorded [our new album], we decided to ditch that whole idea and go with what we want to do instead of trying to stick with one genre and fit the mold of what someone else thinks.”

This mentality, and the resulting power rocking album, has also delivered Scarlet Runner from another stereotype they’ve struggled to overcome – young white guys playing the blues. In the band’s early days, it was often compared to artists like Jonny Lang and Kenny Wayne Shepherd.

“But anymore, people who know about us or people who come to our shows understand that we are doing something that’s a bit different. A lot of people who like us really like those guys, too,” he adds. “But I don’t know if we’re viewed in the same little club as them anymore, which I think is good. I think it’s better to have your own club.”