If you are wondering how well Google knows you just based on your search history, the short answer is REALLY well.
About 2 years ago Google’s ad settings page was released on the internet. This page shows your advertisement profile, which enables Google to assess your age, gender and interests. All this information is collected by assessing your search history and then ads are targeted to you based on this information.
You can check out yours, here’s how:
Sign into your personal Google account > Visit the Google ads settings page.
This is how the results will look: