After the policy takes effect you are not allowed to opt out without abandoning Google altogether.
No need to panic. There is still time.
Before the policy takes effect, you have the option of deleting your Google Web History by modifying your settings so that Google is unable to associate data collected about you with your Gmail or YouTube accounts.
The process is simple. Follow the steps below:
1. Go to the google homepage and sign into your account.
2. Click the dropdown menu next to your name in the upper-right hand corner of your screen.
3. Click accounts settings
4. Find the "Services section"
5. Under "Services" there is a sub-section that reads "View, enable, disable web history." Click the link next to it that reads: "Go to Web History."
6. Click on "Remove all Web History"
When you click on "Remove all Web History," a message appears that says "Web History is Paused." What this means is that Google will continue to gather and store information about your web history but it will make all data anonymous.
Google's ability to gather personalized information about you by assigning data to your Gmail and YouTube accounts will remain "Paused" till you click "Resume."