Keyword miscalculation??

I used Niche Finder to do my keyword research. Niche Finder tells me that I have low - lower/medium difficulty keywords.

Nothing was happening the way I thought it should be so I read some posts and it looks like I should have run these keywords on a normal Google search and used the Moz bar to tell me DA.

All the ranking site have high DA. My site has a DA of 48, every one of the sites listed in the top 10 had higher DA than mine.

Is Niche Finder wrong? or out-dated? Or is it a good indication of what the real competition is and I should not worry about the DA and PA of these other sites.

I also was using Yoast for on-page SEO but I tamed that down once it was pointed out to me that I was over optimized.

I know about this niche but, I do not want to waste time on a dog site that will never generate income.
I would rather spend my money promoting sites that will eventually produce.

Since I only have one site I won't be coy with what I am working on.
http://ragingalcoholic.com
I am too invested to just quit unless I know the time and energy is just wasted. This site is only useful to people if it is seen.

I am beginning to think that keywords (I've been using long tail) don't matter to Google anymore. If that is true, there is no way for me to compete against the people in the alcoholism/recovery niche