A DBA is a designation given to a business entity, not a way of creating one.It's going to take time to establish a solid history, just like starting over again as a teenager trying to establish a personal credit profile from scratch.

He is a hard working teenager, for just $10/hour.

There are a range of great renters around colleges that don't leave in the summer and aren't teenagers that reenact scenes from Animal House or Neighbors (2014, the film with Seth Rogan).

I was a teenager so of course I had other interests at the time, and now I'm wishing I would have been more involved.

I love it, so it's worth it for me, but it's not for everyone LOL.I started with my own LLCs from the time I was a teenager running a lawncare business and expanding from there.

Very few teenagers know what they want to do, so you're definitely taking the right steps. 

making your own homemade sploof is a tried and true method that college kids, teenagers, and worried parents have used for years."...now your tenants will always smell like fresh laundry!

We did lose it, however, for a  few years when my kids were teenagers and too many cars were totaled (4 in 2 years), so had to up the liability on all policies separately during that time, but we couldn't get it from anyone else then, either.   

He became an agent when he was a teenager and does very well (I think he's still in his 20s - he invests in real estate as well). 

A big angry dog can do a lot of damage, way more than a very little kid and equal to what a teenager or adult might do as malicious damage.