Why does it say my browser is out of date

What says its out of date?

Are you actually running iOS 12 on your iPad?

If so, then it's because it is out of date. The Safari version included in iOS 12 is fairly outdated at this point.

The website you are trying to access, may need a newer version to be able to access it and for security purposes.

If your iPad model supports a newer version, going to Settings ➜ General ➜ Software Update should initiate the update process if one is available for you model of iPad.

click here ➜ Identify your iPad model - Apple Support

and then here ➜ Update your iPhone or iPad - Apple Support