Just starting out in this great hobby! Yesterday I bought a beautiful little Japanese Maple from a local garden centre for around 30 bucks. I live in Norway and it's a bit late in the year. Will it be a bad idea to pull it out of the plastic pot and do the repot procedure into a bonsai pot with bonsai soil now in August? Or should I let it remain as it is until next spring?

Also, here is a picture of it. From my very beginner point of view, it seems to have decent potential?

Hi, and welcome to the forum.

Yes. This would be a very bad idea.
Repotting & trimming roots is not the easiest thing to do. It can be done in summer (I know, I have done it often) but it does require you knowing what to do & how to care for it afterwards. As you do not have bonsai, you do not know how to care for plants in bonsai substrate making the risk too high.

You certainly seem to have bought a good plant to work with!

Thanks, then I'll keep it in its current pot until next spring before I start doing any work to it.