To answer the OP's question, which is not about whether you should allow Google to cache your page, but rather about what an old cache date tells you...
The cache date is not necessarily indicative of the last crawl date. It might
mean that Google has seen that your page hasn't changed, and it hasn't updated the cache. Use your server logs or reports in the Google Search Console if you want to know when Google last looked at your page.
This from John Mueller, reported by Barry at SER in several articles over the years... Google: Cache Date Not Indicative Of GoogleBot Crawl Rate Nov 21, 2016 - by Barry Schwartz
In his 2016 article, Barry also quotes a 2010 post...
"In general, we do not always update the cached page every time that we crawl a page." He added, that this is especially the case "when the page does not significantly change, we may opt to just keeping the old date on it."
Also, more recently, Barry notes this... Google Wants You To Ignore The Cache Date Sep 12, 2017 - by Barry Schwartz
There are lots of reasons why the cache date isn't significant, and why even the actual crawl date might not tell you what you want to know about page quality.
How often does the content of these pages change?