You may monetize eligible videos without associating an AdSense account with your YouTube account, if you've enabled monetization for your account.
Over time, after you've accumulated more views, you may consider associating an AdSense account with your YouTube account. If you don't already have an active, approved AdSense account before you begin monetizing videos, we'll prompt you when it's a good time for you to create an AdSense account and associate it with your YouTube channel. In order to be paid, you will need to associate an AdSense account.
After successfully associating the two accounts, YouTube may deposit a bonus into your AdSense account. Going forward, your future earnings from the ads served with your videos can be viewed in AdSense and in YouTube Analytics.
You can also associate an AdSense account at any time here.