Developing a career in animation can take almost any amount of time, mostly it is a matter of practice, passion for your art, being creative, and finding ways to share your work. It is also a bit of luck!
When I was in grade school, I loved art, and would draw almost every day. I first created flip-books and simple paper based animation to get started. Eventually I had access to a camera, and was able to start doing short films of my animation. Back then, I mostly did this for my friends and family.
Now, software is available and you can even use mobile phones to film and capture animation.
Animation can take a lot of forms and used in many areas...it could be for entertainment (films, shows), video games, advertising, education, and pure art.
I decided to go to university to study computer science, where I focused on computer graphics. Getting a college degree was purely optional for this field, as it is your art, practicing and gaining experience with your craft and tools (paper, computer software, etc) and building a portfolio of your work that is perhaps most important. College may help make connections though.
What is cool, is now you can develop a career (one that can earn you money), even if you self publish your work on the Internet. YouTube and other social and video services give you a way to build an audience (and take advantage of things like advertising).
You can also visit sites like glassdoor.com to check out places like video game companies to get an idea of what various game studios expect of animators and how much they are paying.
I've known people right out of high school that were publishing animation directly and building indie games that allowed them to start their own small companies.
Hope this helps give you some ideas.
Christopher recommends the following next steps: