I'm a native English speaker, I started studying Russian at age 19, and I was fluent enough to converse with native speakers in a non-annoying way by age 21. Granted, circumstantial evidence from peers does suggest I'm something of an outlier. I've also found that learning a third, fourth, etc. language is much easier once you've already become fluent in a second language. Indeed, when I studied subsequent languages, I would usually take my notes in Russian, to cut the native-language-favoring wiring in my brain out of the process to the extent possible.

I agree to a degree about the practicality of learning the languages, with the caveats that a) there are interesting people to interact with in the world that do not speak English, and knowing more languages expands the set of interesting people one may interact with, and b)if you enjoy reading, literature is generally much better in the original than in translation.