Yes, I think it's worth it. Especially since your employer is paying!
The Associate's Degree itself isn't "worth" that much in dollars over a HS degree in the marketplace, but it is worth it to have that Associate's degree if you ever decide to move on and complete a Bachelor's degree.
When you start a Bachelor's program, you'll be better off in terms of what they will require than if you have a bunch of coursework without the 2 year degree. Think of the Associate's as an "umbrella" that is recognized (almost always) as 2 years of coursework towards a Bachelor's. In other words, there might be courses you took towards your Associate's degree that they wouldn't have accepted towards their Bachelor's degree requirements if they hadn't been included within the "umbrella".
With assorted coursework and no "umbrella", a school looks at your courses in an "a la carte" fashion in light of their 4 year degree requirements and starts fitting your coursework into that framework. So you'll have the last two years of coursework to do, plus you'll need to make up any "gaps" (read: extra courses you'll need to take) from their course requirements leftover from their first two years of requirements.
Of course, all of this really only applies to traditional Associates of Science (AS) and Associates of Arts (AA) degrees. Those degrees are structured to satisfy the general education (gen ed) requirements for a broad based liberal arts education leading to a student transfering to a 4 year school to get a BA or BS.
Echoing what Ronda93 said, if your Associates is an occupational or specialized degree instead, then the situation will be different because these degrees are not looked at in the same way credit-wise towards a traditional Bachelor's degree. You would probably have more than two years of coursework to finish.