Modding can be quite a few things,
It could be writing, designing, concept art, gameplay design, programming, texturing...
Its true that ppl tend to lean more to one side of skills, the more technical or the more artistic. But I for one am someone who can do both quite well. Downside is that I don't excell in any of those skills, I'm not bad, but not great either. call me a 'jack of all trades'.
Point is Alrik, practice makes perfect. You choose an interest and learn it, improve on it, get good at it. But that takes time, and it changed you. If you then find a new interest completly different its indeed hard to learn it, since you are chockfull of other skills & knowledge. But this doesn't mean you can't become a good programmer if you excell in artistic skills, but it will be bloody hard.
And offcourse, there are things like talent, but imo even talent isn't something you're born with.
