Ok, you should try to Clear Cache (using the button from plugin's option page) and Update Options.
For Beginners: To check if tracking is working properly:
1. Go to your Google Analytics Account
2. Select your profile and select Real-Time, then Overview
3. While browsing your website check if there are any new actions recorded
For Advanced Users:
1. Open your website frontend, right click and choose View Source (or use CTRL+U shortcut)
2. Search for (use CTRL+F) UA-, if you can find it then the tracking code is active.
3. You should also check if the inserted UA- code is the right one for your website