If you want to learn a language and become fluent in it, you really need to start as early in life as possible, because the older you get, the harder it can be to get your tongue round new words and sounds. However, that is not a reason to put off learning a language later in life, because there are still many advantages to it.
As you get older, it can become more and more tempting to stick to things you are most familiar with. However, giving yourself something new to do can help to keep your brain active, and the more active your brain is, the younger you will feel.
We all need new challenges every now and again. It makes life interesting. Don't set your expectations too high—you aren't going to become fluent in a couple of months, for example. Instead, set yourself short-term goals—to finish a text-book or to practice your skills on a language speaker. The challenge will provide you with a renewed energy for life.
Many people, especially when they are older, put off going overseas because they are worried about communicating with the local people. However, once you start to learn a language, you will have much more confidence to travel in countries where the language is spoken. Once you are able to buy things, ask directions and have free conversations, you will find traveling much more enjoyable.
One of the best reasons for learning a language later in life is simply because you can. When younger, you probably had little spare time. Now, you probably have more time in hand because your family has grown up and you may even have retired. There are so many tools you can use to learn languages these days (the television and Internet are two obvious ones), so you may not even have to pay.