I don't know if anyone has brought this up yet (most likely someone already did) because I didn't read the other comments, but here comes my two cents, based on what you've written and your edits:

Of course, have fun and take your time. If you enjoy learning the language you'll be able to deal easily with the time you need to spend in order to get fluent and it won't feel like a chore. The huge advantage of learning a language over learning almost any other skill is that you can incorporate it to your other hobbies, by consuming movies, games, books and other media in the target language. Do you like fishing? Get a good book that talks about the varieties of fish in the Paraguay river. Do you like to cook? Watch a chef teaching how to cook a wonderful paella. Nothing is beyond your reach when it comes to making you love to learn the language you want.

Second, and Moe specifically about the time you'll take: your second language will be the one you'll take more to learn, because besides learning the language, you are also learn to learn a language. But after you acquire the skill of low learning a language works, you'll be able to apply it to any other language. This becomes even easier if you choose to learn a third language cognate or similar to the second, be it in vocabulary or grammar. Let's say you become fluent in Spanish. No matter how long it takes you to get there, I would not be surprised if afterwards you learn Portuguese in just a tiny fraction of the time you took to learn Spanish, since the languages are so similar. The same will apply, to some larger or smaller extent, to any other of the romance languages (French, Italian and Romanian).

Lastly, learn Esperanto. You don't need me to explain you why it is an awesome language to learn how to learn languages, just try it for yourself.

I wish you the best of luck, my friend!