Inner page index and deindex

Hello

I just posted one new post on my website and then i went to google add url.. This post was indexed almost instant.. So when i go checking site:inner post some time the post is indexed and some time deindexed. Also rankings don't show up ?

Website is 7 months old.

Its normal thing with recent Google updates, Once your site got high authority, the ranking will be more stable and there will be no deindex and all that issue.