This is great advice!Find a very competent piano player to hang with will have so many advantages to mosthack guitarist. (better yet, play piano yourself) Learn chordal and extension theory. Get and study the Real books. Listen to the American Song book and Jazz standards played by jazz masters countless times. (I grew up with these). If they do not appeal to you on a deep level, maybe jazz is not the best direction for you.
Good piano players can show you a wealth of practical theory and playing skills. I hooked up with an older bona fide jazz pianist and it was like a graduate course in jazz.