I'm studying PHP lately but I like Wordpress a lot. Is it possible to understand how web development and PHP works through Wordpress? you know learning how to build themes and plugins with Wordpress?
Definitely! But there are two sides to that. The WordPress way and the not so WordPress way whatever that tends to be. WordPress makes a lot of things really simple by using wrapper functions and making core API's available to help make development easier on the platform. In turn some vital aspects of PHP won't make it into your skill set at least in the beginning. Things like creating a socket for the DB, CRUD and stuff like that. I wouldn't consider that much of anything to worry about though because you would still be learning PHP in the end. The cool thing about WordPress is that the community is pretty awesome and amount of good information you can find is vast. In the end though code is code so just pick something you enjoy learning and working with because the possibilities are endless and eventually you'll be learning something new anyways.