My apologies, I thought you meant you haven't seen a Ghibli movie. Excuse my dyslexic ass. Yeah, a few local film festivals sometimes put Ghibli movies for theatre showings. You are right though, this may actually be my first new Ghibli movie I'll see in a theatre screen, I'm keen.
Prime time for you to discover and fall in love with Studio Ghibli movies. I suggest working your way through Spirited Away, Howl's Moving Castle and Princess Mononoke, to get a feel of what to expect in terms of storytelling, visuals and sound tracking. Of its your cup of tea, their older discogs are truly amazing as well.
I envy you that you get to experience the Ghibli experience for the first time.