Learning a foreign language can take a lifetime. Even if you lived in a country in which a foreign language was spoken it would still take you many years to fully understand the slang, jokes, and cultural differences. Even still, it is possible to learn a new language if you are willing to put in the effort.
First, look for a course that will help you to learn French online. Because it is easy to find free online resources that are both comprehensive and up to date, you can plan out your course of study quickly. In some cases, it may be a good idea to work with a native French instructor, however, you can still get a basic understanding on your own.
If you want to learn French quickly then it is best to speak it with other people that are learning. You can carry on casual conversations that will help you to challenge yourself. Using visual aids that will help you to trigger your memory will also assist you when you are unable to think of a particular word or phrase. As long as you are open to the idea of trying out different methods you will find that learning French is a joy and not a burden.