Is Learning 3 Languages at Once Realistic?

So I'm very good at languages. I tutor English and Spanish and I am currently taking French and am catching on very quickly. I also want to learn Arabic and Russian as quickly as possibly. I am getting the Rosetta Stone (not the best program, but I can get it for free) for Arabic, Russian, and French. Is it realistic to learn all three at once? I'm also taking 5 classes in college. I think because the languages are so different from each other that I won't get them confused, but that is also a detriment because it is three completely separate grammatical rules and vocabulary that I need to learn. Should I just stick with French? Or French and Arabic and wait a little bit till I start Russian? Within ten years I want to be fluent in those three and another. Any suggestions? I was thinking Pashto or Farsi. Possibly German.