I may be a bit of a rebel, but color selections don't matter that much, but the <b>relative</b> colors do.
in this I might have slapped in a rich purple sky,
I may have hated it and dropped some green on top to echo the street sign (I would have obfuscated the words on that, since I don't want people to read my art I want them just to breathe it.)
in some places the purple would remain and it's relationship to the orage would be exciting, of course I would have to make the green look great too, how? just by going at it and making mistakes.
the more you know beforehand the more stilted the results will be.
working with acrylics is easier than watercolor so you may be starting with a difficult medium.
you certainly can draw, and it's clear you like shadow which is a great thing in itself, since painting it often transcends objects.
fun da mental