It's not like British and American English. Latin and European Spanish sound more similar to each other than comparing British with American!! They both follow the same Language Academy, so if you grab a text written by a Latin spanish and an European spanish speaker, you'll hardly notice a difference. As to the accents, they're different but not to the point that you can't understand!! The slang words and some detailed vocabularies could be the tricky part!!! But that, with time, you get to learn!!

No, no tendras dificultad porque son la misma base, solo cambia el acento y los modismos.

It's similar to British and American English..they have difference, but they can understand each other