Learning two languages at once

I am posing a question for anyone out there who has an answer. I have to take Spanish for my college courses, but I am also trying to learn Portuguese on the side. Because they are similar languages (or at least seem to be, so far), it isn't too hard for me to pick up both of them at once. However, in the long run, do you think that this will hinder me? And for those of you who have gone through something like this before, will I glean the same ability out of this?