Castellano vs. Español

[aycaramba]

Hola,

I'm currently learning Spanish because a lot of my family members speak the language and I'm eager to learn it as I find it a beautiful language. I started taking online lessons Spanish, but as I live in Europe I've got my doubts whether to continue learning 'Latin American Spanish' or begin to learn Castellano. I've made good progress learning 'Latin American Spanish' and I have to say I have no problems at all regarding the grammar and the vocabulary. So now my question is, since I'm gonna be visiting Spain a lot, would it be better if I stopped taking those 'Latin American Spanish' lessons and began to start learning Castellano? Or should I continue since I think the adaptation won't be really hard? It might seem as if there is no difference between the two languages, but mind you that the vocabulary and the slang can differ very much from each other, as well as the pronunciation, even though the pronunciation isn't gonna be a real problem for me...