Keep updating
You've got maximum 30 seconds to recall your message, but you must configure your account's settings.
Source: Gmail: Getting Started
By default, you have 5 seconds to undo sending an email.
To change the Undo Send cancellation period:
Minimize the email message to see more of the gmail window, then, in the top right, click Settings Setting gear icon > See All Settings.
On the General tab, scroll to the Undo Send feature.
The Undo Send feature location on the Settings' General tabbed page
Change the cancellation period to 30 seconds.
Scroll to the bottom and click Save Changes.
Click on Drafts folder and then click on your email to restore it to screen, then click Send.
Notice that you have more time to undo sending the email.