This is a tough predicament but I refuse to say that it's impossible to get a career in UX without a BS/BA.
One of the things you can do that comes to mind is to create a blog about user experience - that's a start. Your blog entries must include:
- Personal frustrations with specific UI from various devices - not just software. Look around in your kitchen. There's a ton of usability issues in microwaves, toasters, refrigerators, blenders, etc. Also, pay close attention to non-electronic devices like locks, door knobs, and the shower (ugh, lots of terrible designs here especially regarding the temperature of the water). Include screen shots.
- Your proposed solutions to anything you write about from #1. This demonstrates that you know what goes through users' minds and how you'll make it easier for more people to use things. Include screen shots of your solutions. (You will probably need to use software such as Illustrator, Photoshop, or Gimp (Free) - and by using these programs, you will find usability issues that you might want to address in your blog.)
- Knowledge of UX principles (you will need to do some reading and research), and how a principle solves a specific usability issue.
- Review an existing software or website. Write about what they did right and what they could improve based on your experience and research.
Ensure that users can comment on your entries and that you correspond timely and accordingly.
If you decide to earn a degree with UX in mind as your ultimate goal, you could go for Communication, Organizational Studies, or even general studies (because they would address issues about how people receive info, think, and work through things). You wouldn't need Digital Multimedia, Computer Science, or Engineering - those would be overkill for your goal, though I would personally encourage you to go for them if you want.