You are correct. The default setup for Yosemite is to go to the login window at boot.
You can change that in your System Preferences/Users & Groups pane.
Click the padlock to unlock that pane, then change Automatic Login from "Off" to your user name by clicking on that drop-down. It will ask you for your account password when you make that change. The next restart or boot will take you straight to your desktop with no stop at the login window.
I should remind you that your system will be somewhat less secure, but if you are OK with that, who cares what I think!