Was in this exact boat. My knowledge of soccer is extremely basic, and I've probably watched less than 20 games in my life. That said...yeah, it'll take lots of games, but playing to a level of not making a fool of yourself isn't difficult.
Terminology and basic scoring and defense stratgies come easily and intuitively. Learning the controls, specifically learning when to use certain stuff can be somewhat difficult. Grinding away at the Virtual Pro achivements in exhibitions can really help with this. The hardest part for me was learning the proper field position for the various positions, and what the formations mean. Since in Virtual Pro mode the game likes to deduct from your score if you're out of position, I found it best to really pay attention to where guys were off the ball so I could try and replicate that when running around. For formations, I had to actually do some googling. I'm still not good enough to be switching formations willy nilly, but I know where my VP is supposed to be which is good enough for now.
Flipping around the menus can be a real struggle at first, but it's not so bad when you figure out who plays in what league, and all of the different layouts. FIFA is like having 40 soccer games in one or something with all of the different leagues.
Playing this game really made me realize how intimidating modern sports sims can be for someone who isn't used to the minutae of a given sport, but if you're posting on this forum you should be game enough to get things down in a couple weeks.