Google Won't Cache My Site

So I have a site that's 2 months old already, but Google just won't cache the homepage, while some of the inner pages has been cached.
My site even already ranked top 10 and top 20 on some keywords.

Never had this issue with my other sites.

Any idea why and how to solve this? Or is it no concern at all?

Thanks.

Turn off the NoArchive directive on settings, that removes such directive from your page and enables search engine to cache your page

some time its happening.. I also faced the same issue and later google will automatically cache your home page too.. please wait a while.