Check out this article that states adults can learn just as quickly as children can. That means you can learn French as easily as your 5-year-old sister/daughter/etc. so learn it.
Then travel the world!
Some awesome passages from the article; Old schooled: You never stop learning like a child
“The mature brain, it turns out, is more supple than anyone thought. “The idea that there’s a critical period for learning in childhood is overrated,” says Gary Marcus, a psychologist at New York University.”
“Adults can hamper progress with their own perfectionism: whereas children throw themselves into tasks, adults often agonise over the mechanics of the movements, trying to conceptualise exactly what is required. This could be one of our biggest downfalls. “Adults think so much more about what they are doing,” says Gabriele Wulf at the University of Nevada, Las Vegas. “Children just copy what they see.”
Wulf’s work over the past decade shows that you should focus on the outcome of your actions rather than the intricacies of the movements. She applies this finding in her own life: as a keen golfer, she has found it is better to think about the swing of the club, for instance, rather than the position of her hands. “I’m always trying to find where best to focus my attention,” she says. Similarly, if you are learning to sing, then you should concentrate on the tone of the voice, rather than on the larynx or the placement of the tongue. Study after study shows that simply shifting your mindset in this way accelerates your learning– perhaps by encouraging the subconscious, automatic movements that mark proficiency.”
“Although the reason is still unclear, it seems that jumping between skills makes your mind work a little harder when applying what you’ve learned, helping you to retain the knowledge in the long term – a finding that has helped people improve in activities ranging from tennis and kayaking to pistol shooting.”