Yes it is - providing you are willing to learn the trade yourself.
I've been freelancing as a php developer since I was 20 years old. Now that I am 26 I have landed a decently paid full time php/sysadmin job that I really enjoy.
Between the ages of around 14 and 20 I spent a lot of time messing around with html and playing with linux installations which gave me the foundation to learn more advanced skills later on.
My main advice would be to take any job that you feel will increase your knowledge. If you don't like it, change jobs after a year or two.
Get some friends who work in the area of tech that you want to move into and talk with them about their solutions to problems.
If you can't find any friends in real life then find some on irc/reddit/hackernews/github...
Other people (and other people's code) can often provide you with a far better education than a degree.
One last thing - if you know anyone who is currently doing a computer science degree ask them what books they are learning from (for example books about object oriented programming eg java, books about database normalization, books about project planning).
There is a goldmine of knowledge out there providing you are interested to use it!