Coding is also a way of thinking. Too much planning up front also has a name (water fall?), the other option is to write now to get understanding and rewrite later as that understanding accumulates (I think that way if working has a name also).

Of course, there are many kinds of valid working styles in between. I personally would rather see juniors write, make mistakes, and rewrite than just be paralyzed with thought/planning anxiety, which is perhaps more effective for more experienced developers.