I would like to know if position of meta tags like:
<meta name="description" content="....">
<meta name="keywords" content="....">
given they are inside <head> tag, matters for SEO.
I mean, is there a difference, SEO-wise, if they are positioned at the beginning of head or at the end of head (after all the CSS and JavaScript inclusions)?
No, the position of these tags within the head does not effect SEO.
In fact - these tags don't directly affect search engine ranking at all (at least on google where they are not a Ranking Factor), only indirectly (by how enticing they are to users, therefore influencing the click-through rating).
More info is available on that here: https://moz.com/learn/seo/meta-description
<HEAD>. – Simon Hayter♦ Oct 30 '17 at 13:10