If you haven't used any other OS than Windows, then you are in for quite a steep learning curve with FreeBSD. FreeBSD has no "default GUI", only pure console so if that is going to be a problem I suggest that you start with either PC-BSD
which is a FreeBSD derivative(ie based on FreeBSD) or if that's still to technical then I would suggest one of the extremely user friendly Linux distributions like Ubuntu or Fedora.
In general, my suggestion would be to start running the open variants of the software that you currently use in you existing environment. Like Eclipse for java, pidgin for IM, Firefox/Opera for Web, Thunderbird for email, OpenOffice for all that it can do, VLC for media and so on. This will make the change to another OS easier when you have the same applications on both platforms.
Also if you just what to "try it out", I suggest that you download VirtualBox and install anything you want to try first in that virtual environment as it will not compromise you current OS(usually by accident).
In the end, you will come to a point where it's all or nothing and how well you survive that is all down to how much you have prepared.