1st Time Shoplifting, 3rd Degree, Washington

So back a couple months ago I received a civil demand in the mail like a good boy I am I payed it the next day. thinking it was over due to some of the threads on I read on here dealing with Sears... I received a letter in the mail today.
From the gist of what I have read today I'll be a "slap on the wrist"
a 100-600$ fine A mark on my record and maybe some community service time... and since I can't afford a defender I go to a public defender, going to google that soon...

So the Run down so far was
Washington
Sears
under 250$-- 3rd degree
19 years old
Police where called but did not come.
caught stealing 107$ of items for personal use.
307$ fine in the mail.
paid the fine in full.
Letter asking me to go to court.
what happens next?

Should I plead "guilty" or "not guilty"? The store does have video tapes (me walking with items in my bag behind a rack or some kind then leaving) would this action condemn me?

Will it matter that I am a senior in high school trying to graduate, with Ap classes? The fact that I should be responsible. It was bad judgment on my part. It was my first and last time I will commit any crime.

I'm also part handicapped or disabled. Or at least I have to mark it down on the disabled/handicapped page when I worked at my last couple of jobs.

what next I'm not to sure about but any advice or insight into this topic would help me greatly appreciated!

[QUOTE]I'm also part handicapped or disabled. Or at least I have to mark it down on the disabled/handicapped page when I worked at my last couple of jobs.[QUOTE]

What is the nature of your disability?
Why do you have to mark it down?

It is a speech disability nothing to major. but at times it can be very hard to comprehend what I'm saying