Yeah. You've got a 10.5 on iOS 10 IIRC. I would stay. I'm even worse: my 9.7 Pro is on iOS 9. I'd like some of the features of iOS 12. The control center and screen recording was also something I've wanted for a long time. But it is what it is. My iPhone 6s is on iOS 9 too. I don't have the features. I don't have the app compatibility, and it'll only get worse once iOS 12.0 is officially launched. But in the end, it works so flawlessly that I won't even think about updating.
I actually had tried iOS 11 on it last September and thanks to the ProMotion display, I could see minor stuttering and an awful battery drain on it. Whenever I get that upgrade itch I remember that experience and it goes away. iOS 12 is nice but I am not sure its iOS 10 nice atm