Few months ago, I asked a similar question about learning two languages simultaneously and this is one of answers  I got. Hope you find it helpful. :)


"I'm going to just ignore the "how" and suggest that you not do this. Humans are not especially good at multitasking or learning new abilities simultaneously, even if we tell ourselves otherwise. Pick one language, fully immerse yourself in it, work your ass off until it's very good, and THEN go to a new one. Learning two, even if they're very different, will still be potentially confusing, and it's going to take a lot longer to see nice results with either one. In fewer words, focus on one and then on the other. Don't worry about what other people are doing; staying single-minded will likely help in the long run."

Although I am not "old" I can say, that it is even easier. My grand-frather who is 91 is learning 2 languages (Russian, German, but he had strong rudiments, before)and in 2-3 years he has made bigger progress than myself in 5-6 years. So, everything depends.

Besides, there are no old people, only with "bigger experience".

I think it makes a big difference whether you are old or not. 

A child of 7 or 8 still has a limited vocabulary and base ability in the native language even though they were in total immersion the entire time. I can get there much faster than that. 

The older I get the easier it gets too! I know more about my brain now that I am a senior citizen and I have finally figured out how to learn. I know what works for me and what doesn't. 

I spent many years exercising my brain and developing observational and cognitive skills that I didn't have when I was younger. 

I have learned patience. I don't think that I have to learn something in 3 months. I can make 5 or 10 year plans with ease and comfort. A year in the perspective of my life is a very short time whereas to young people it seems like an eternity. The older I get, the more patient I get. 

to be continued....

I think that age does not matter, as long as you've already learned a second language.  The more I know about language, the more I believe it is a tool for communication.  I don't think one can confuse with different langauges when learning more than one, especially those are of from different language family. 

Hello!

   I think you -as a native English speaker- have a privelage of learn a romance language faster than us. You can pick up vocabilaries faster if you learn true cognates. In your case, French -German- English cognates. I am learning Spanish through English and it is mush easier than learn it through Arabic. I rather not tell a false hope because people get frusturate easy because of it. You may need at least three years before you speak the language and it has nothing to do with age. It is more related to hard working and reputence .Arabic is different and it need another technique. Arabic learner may give you better advice than mine.