how much shouild I wait to know that google won’t index my post?

It's been a week and google didn't index my post yet. I changed the theme and deleted all posts and made a new one .

The homepage got indexed but the only post I got still didn't get indexed. The post is 1500+ words. But the google speed test is showing an server respond error, Could that be the reason the post isn't indexed?

Can you recommend me any plugin that will help get my posts indexed faster?