Declaring Misdemeanor Tier 4 Visa Help!!

Hi!
I'm new to the forum and have just started the application for my tier 4 visa.
This summer I got into legal trouble at work during a sting operation/compliance check when I failed to check a minor's ID for selling alcohol at work. I hired a lawyer immediately and it was resolved when I signed a Delayed Prosecution Agreement. The agreement stated that after I completed community service hours and paid my fines the charges would be dismissed.
I'm not sure if the agreement is considered a guilty plea or a charge or anything.
I asked my lawyer about the question on the visa application about criminal history and she said that none of the options applied and that I could answer no to all, but I'm not sure how that works (she isn't an immigration lawyer and we didn't hire her to help with the visa process) and from what I've read it seems like I should declare it on my application.

Do I have to declare the incident even though it will be removed from my record?
Should I wait to apply for the visa until the incident is completely removed from my record?
Will it affect my chances of getting approved for a visa?
Has anyone been in a similar situation?
Help!!!!