If you are thinking of getting started with WordPress, It's the best video series to learn from scratch

Please complete html, css, psd to html, responsive web design and php first to get started with this video series

if you think you are not perfect enough in Responsive Web Design with CSS3 and HTML5 without Bootstrap, then please complete Responsive Web Design and PHP and then get started with wordpress.. It's just a suggestion to keep you on the correct guideline

Good Luck !

Topic: Premium Theme Customization