Cannot manually delete favorites in Safari in iOS 10.3.2
It's going to be very difficult to troubleshoot this based on the info you've provided.  

Honestly, the iPad 4 is considered 'old' (introduced in 2012).  It does support the iOS version you're using but, like a 102 year-old man, it will struggle with some seemingly basic tasks like putting his pants on and using a spoon, simply because it's old.  

If a reset didn't help, your only option might be to buy a new(er) device.