I could say it's normal but you're just lucky enough that you instantly indexed. Some are having problems with indexing in Google.
Yeah.. Just don't worry about that. Be happy cos you're lucky to be crawled by Google as fast as that.
Just got a better explanation from a friend like why I got my new website and its posts indexed so fast... It is because Google is now try to catch up with twitter in terms of indexing articles, so google have to make sure they index the article at the same time or before twitter does and they adjust their crawl rate on every websites that have big traffic volume and blogger is one of them, You will notice like here in DP we will know when Google is Crawling its pages when you start experiencing getting disconnected from the site or sometimes gets Page Error while the page about to load.. Google Crawler causes the server to become very busy but the good thing here is that google gets your article indexed in few minutes.