The target of the series is not focused in particular on an age group between young people and adults. According to interviews published later with Akira Toriyama:
In a “Special Interview” with Toriyama in the May 2013 issue of Shueisha’s V-Jump:
Let’s see. Well, it hasn’t changed from when I was drawing Dragon Ball. At the time, since it’s a boys’ magazine, the readers are boys, so I was particular about “not making it too convoluted”. So it was the same with the movie: I was particular about kids being able to enjoy it.
Also what he mentions is his book:
I was conscious of having content that children could understand, and not getting too serious. Also, this time there is a “god” as the subject, I thought I should make it light so it wouldn’t get religion-y. And also, I was careful not to give them difficult, abstract/conceptual dialogue.