I would disagree. You might already know a language that is very similar to another language because they stem from the same proto-language. Then it won't be that hard to learn. And many times the more you know it will help you with other languages. If you know French and English you'll probably have a pleasant time learning Spanish. You can get the subtleties by interacting with locals, and with the internet you can do that online. There are apps for language exchange and you literally choose a location and start to chat and talk with people from there and you'll also get cultural aspects. It's just important to immerse yourself. But I think it's incredibly rewarding to learn a language for the sheer amount of new content you get to consume, be it books, television, music, etc. You get to explore a whole new territory of things and culture which is amazing at any age. I guess whether the accent matters is a personal thing, personally I don't mind an accent. I'm not trying to imitate a local and change my whole identity, I'm trying to understand and be able to communicate.