The people who compliment me on my Chinese consists of two different groups: Chinese who are trying to be polite, and Americans who are surprised when anyone learns a foreign language.
Do not make the mistake of learning it when you're old. If you do, you'll find that Chinese is the one language easier to speak then to understand. All Chinese seem to think the Qing Army is on their trail and they have to speak as quickly as they can or be brought down by an arrow. Every minute of conversation gets worse because they assume you understand the sentences that came before. You can say "yaoshi ni hen man. ke neng wo ke yi zhi dao." (Which means, "if you can speak slowly, perhaps I can understand." They may speak slowly for one sentence but quickly forget and leave you in the linguistic dust.
To show how you have to pronounce each word in the perfect way, let's take the word "ma." Depending on the way you pronounce it, it can mean mother, horse, question, trouble, or marijuana. And you think German is hard.
Of course, except for some second-generation Chinese-Americans, only enormously driven Meiguoren (Americans) speak the language. I've taught many Chinese nationals American idioms, and I wonder why more people here aren't learning Chinese. "Wei li" is a way to say "the future" in Chinese. People are still learning French in high school. When France was looking for a place to celebrate the virtues of French, the only place they could find was in Vietnam. French was once the "lingua franca." Now the Germans talk to the French in English. The Italians talk to the Norwegians in English. Germans may try learning French, but almost always you will see a French student learning a Romance language, which is much easier than German or any other language.
Americans should try to learn Chinese (putang hua) but they should realize it's going to be much more difficult than high school French. Then we can get a benchmark on how our K-12 system is working. Having taught at a state university for 30 years, we'll find out it isn't.