No you always want to use the built in version of jQuery with WordPress. The reason is, if there’s a plugin that needs jQuery that plugin will use the default WP version (or at least it should) and if you load a different version you might run into version conflicts.
I had this happen on a site a client asked me to fix. There were three different version of jQuery loaded on one page, and causing a plugin not to work.
And you always want to use wp_enqueue_script() so you don’t have multiple instances of if loading.