Thank you juniper222, I did, right after writing my original post, look up Massachusetts nursing attorneys because I realized that I just didn't want to decide how to proceed, no matter what, without professional guidance. I had a conversation with an attorney who could not take my case because he only deals with insurance issues and does not take private clients. First, he recommended an experienced Massachusetts nursing attorney who could perhaps write my response to the board. After, he talked awhile about a few things I thought I would mention here for anyone in the same predicament later who finds this thread.
In Massachusetts, he told me, the background check goes back a max of 10 years. So if I hadn't provided the info the board would never have known this 15 yr old judgment (he did say that obviously you want to be forthcoming but it's still an interesting fact that I doubt many people know when they are answering the board's initial questionnaire for licensure that asks about any criminal history). He also said that my argument is rather credible sounding on its own, especially given that it was so long ago and I have no other criminal hx or disciplinary actions. He said it would be wise for me, though, to now provide the board with character references especially from any long-time employer, church leader, or police-type of sources that have known me a while. For instance, he mentioned it would be good if I was married to a cop (which I'm not, and I've never belonged to a church). He said that type of additional evidence would really help. However, he added "the board here, just like any state nursing board, can be fickle or someone could have a bad day and reject your application" which he said is why it was good I was taking this seriously because if they did decide my argument was not good enough and rejected my application it would COUNT AS A DISCIPLINARY ACTION going forward so even if I applied for RN licensure in another state instead after this, I would have to list this now as a disciplinary action. So this predicament really has the potential to mess me up long term, just based off how well I argued that I am not, basically, a person with alcohol dependence who should be in recovery because of a one-time DUI I got at a very young age, 12 years before I became a nurse, which is also such an old judgment I did not even have to technically disclose it. I have often had to remind myself when I start to say these things about how long ago it was and how it was a one-time thing and not indicative of my life since then, that I literally could have killed someone that night that I did get my DUI. Any other alternative (such as not being able to be a nurse) is of such lesser consequence. The cops that night could have been saving a life, who knows. I admit its difficult to always keep this fact in mind when I am in the midst of this stressful situation with the board here.
To keep this post from being really, really long though, I will just wrap up by saying I do think I am definitely adding to the benefit of society as a nurse, however, so I do think it benefits this state to allow me to continue my profession, and yes I am hiring a good nurse attorney now.