Apple Software Update not loading

If you are actually on iOS 11, you've missed a fair number of updates, which means doing over the air becomes impossible when you don't stay current. Instead, connect your iPad to your home computer and update the software using iTunes.

This link provides directions on how to do that: Update your iPhone, iPad, or iPod touch - Apple Support

Pay attention to the section about Update your device using iTunes.

Exactly what model/generation is your iPad? And, which iOS are you running? It could be that yours has reached the end of iOS upgradeability.

Good. I'm glad it worked for you.