I'm more of a coder, a friend I work with is more of an SEO/marketing guy.
Both of us know that Meta Tags are only one tiny part of the SEO equation but he thinks that the title, keywords and description should come right after the <HEAD> tag, Generally I have a content type right after the head tag, then the others. My content types look like the one below.
Last year I had a interview with a digital marketing company, the digital manager went out of his way to to show me coding stratagy in which hes placed his meta tags at the very top, to be fair he had success with his pages in the serps from what I could see. However I would put them as close to the top as possible without compromising the coding.