It depends also on your motivation. Why are you learning the language? Is it a life time learning or learning for employment purposes. If you are learning one of those languages as a requirement for a job you have to intensify your efforts and give that language more attention than the others, otherwise you can just distribute your time and effort equally upon them. Your brain is able to compartmentalize the words you learn and thus the languages,that doesn't mean you won't get confused or mix up words and the key to preventing this confusion is to put the languages in immediate and regular use and practice such as online chat ,speaking in real or reading. If time is not an obstacle and you have enough time to do that then nothing is left but to wish you the best :)

Hello Jared, You surely can make it! German and Spanish languages are not so similar and Chinese is totally different . When you set your task on learning many languages at the same time,you might end up learning a little bit of many;that is why many people wouldn't recommend learning more than one language at a time.But i think with some time management you can make it,specially that learning a language already increases your cognitive skills which would help you learn another language simultaneously. Some people might think if you are working or pursuing some studies at the university your time schedule won't allow all that unless that is all you have to do in your life; but again not necessarily and you better test your own capabilities. You are already at an intermediate level in Spanish so once you start your German course your attention will shift a little, so you can concentrate for a certain period of time on establishing an elementary level in German language, then you can practice and improve them at the same time. I recommend you to concentrate on the newly acquired language for a while then pursue all of them .Be sure that your learning of a second or third language will not slow down your acquirement of the main language you are studying. Sometimes you might mix up words if the languages are too similar such as Spanish and Italian for example. But in case of German,Spanish and Chinese they are quite distinguishable that such an interference is not likely to happen.

I think you should do it. You'll be surprised to learn that german is maybe easier than spanish- not because it's simpler, but because german is actually really close to english. German and english branched off a few cneturies back and a lot of the roots are the same, like French and Italian are to Spanish. So I think you should go for it. The usual warnings about learning languages are intended for the normal person. You are clearly a language fanatic, and that's a good thing. You should indulge your love for language every chance you get.