Shocked to see that this was Robin Williams first movie!

I've had this film on VHS for as long as I can remember, probably there since before I was born (only realising that now). I watched it a few times when I was a kid, hardly remember it at all so might give it a watch again while I'm going through as many Robin Williams films as I can remembering and celebrating him due to his devastating early death. But I actually can't believe how old this film is when looking back at Robins biography on here I could've sworn this was a 90's movie and his work like Mork & Mindy, Dead Poets, Fisher King, Hook and even Mrs. Doubtfire where all made before this, but for it to be what seems like his first movie in 1980 is crazy to me, never would've guessed it! I suppose when I actually watch it again it may look as old as it is. Probably a meaningless post but just couldn't help myself..