Which foreign language do you guys think it is better to take at high school (all 4 years), Mandarin or German? If I take Mandarin will I be fluent when I finish high school?
You likely wont be fluent for either language after taking 4 years of high school language. Mandarin would probably be the more useful one in the long run.
Mandarin would also be more impressive because it’s more complicated than german since you have to learn all the characters
What do you want to major in? Do you have a career in mind?
The most important thing is that you take 4 years of A language…for the average student, which one it is is not important. Which one do you think you would do better in?
Also think about the enrollment…are there enough students in the class to keep it going for 4 years?
colleges do not look upon taking chinese more favorably than german! after 4 years of any language, in a decent high school, you will have some fluency, of course. how much, depends on the teacher and the quality of the program. it’s plain silly to take a language so different from your own, with a different alphabet, one you may or may not travel to in the future, one that you are not demonstrating any real passion for, and think that this adds value to you as a person and college applicant. and the decision should not be made on which one you would do better in. bad perspective on life, as if applying and being accepted to college were an endgame. so, the question in, if you have no affinity toward any one language, where do you see yourself living in the future? what job? if you’re not a big traveler, spanish will likely be most useful within the u.s. if you love europe and want to travel the countries there, take french or german. if you plan on studying finance, outside of wall street, zurich and frankfurt are the places to be – german speaking! of the main languages taught in american high school, chinese is the least useful and hardest to retain. i am asian, believe me – i was forced to learn chinese as a kid. some characters will be useful when traveling to asia, but chinese is only good in china.
Where would you like to visit?
(note that Mandarin is but one variation of Chinese spoken in China).
What career are you thinking of?
Would you consider a language flagship for college?
http://www.thelanguageflagship.org/content/chinese
Thank you guys. I am going to take German at my high school and Spanish online (my native language is Portuguese which is very similar to Spanish, so it will not be a problem). I am going to try to complete 4 years of each. It might be difficult but I am really good with languages.
Note that the Consulates (Portugal and Brazil) offer classes and certificates indicating level reached. It’d be very rare to have 4 years of German and Spanish… plus a certificate in Portuguese. 
(You’re right that learning Spanish for a Portuguese speaker should be relatively easier.)
No, you will definitely not be fluent in any of those languages after 4 years. I’ve been taking French since 8th grade (Junior now), and I still have trouble with listening comprehension.
I’d say mandarin would look better than German on your college app because it’s harder and more useful.
I would say, from a cynical college application strategy perspective, that you should take the language that opens up the most OTHER interesting opportunities. Given your in Portugal, that might be German. Or China? Not sure: but think of the “second-order” possibilities for your language selection. That’s what will make the biggest difference in your application.
First of all, Mandarin is a tonal language. That is a complete trap.
Secondly, German is an absolutely disgusting language.
I recommend security languages like Arabic, or Russian
Or learn Klingon i think colleges will love that
Take the language you want to take; don’t consider what others think.
You get fluent by speaking the language exclusively (or nearly so) for at least six months, usually by living in the country, and working and living in the language. You can speak complete sentences long before you can understand someone speaking even simple sentences at normal speed (which means thinking in the language, not translating).
I lived in Germany for five years so am fluent; I have studied Mandarin for 20 years (1 1/2 hours per week in class, plus homework) and I’ll probably never be fluent.