My iPad says the software is up-to-date version 12.5. Why can’t I download iOS 13? It doesn’t even give me the option.

Your iPad model is too old, lacking the necessary memory for newer iPadOS versions.

There are no hardware upgrades.

Your option here is a newer or new iPad.

All of which will be substantially more capable than the iPad you presently have.

A first generation iPad Air, iPad mini2 and mini3 can only be updated to iOS 12.5.1.

Apple ended major update support for these models of iPad in September 2019 - although they since continue to received “point” security updates. These devices cannot be updated to iPadOS 13 (or any later major versions of iPadOS) as the internal hardware does not meet the minimum technical requirements (CPU and RAM) for newer versions of iOS/iPadOS.

Some App developers have dropped support for iOS versions preceding iOS 13.x for technical reasons (often because APIs or software libraries upon which they rely have been updated in the new version of iPadOS, making their App incompatible with earlier versions). 

Whilst many App titles remain compatible with your iPad, if you want or need to access to Apps requiring the most recent versions of iOS, you’ll need to consider replacement of your iPad with a newer or current model that supports iPadOS14.

Sorry, I appreciate that this may not be what you were hoping to learn.

I hope this information provides helpful clarity as to your available options - and the limitations of your existing iPad Air.

The app store indicates iOS 9 or later on any iPad.

Free space required is ~300 MB, plus probably double that for install.

Here’s the Cookie Jam support website: https://jamcity.helpshift.com/a/cookie-jam/?s=contact-support&f=contacting-support-for-ios-mobile-players&l=en and there’s a contact link on the upper right of that webpage as you won’t be able to use the in-game button.

Also, just to cover all possible issues, what is the rated, internal data storage space/capacity of your iPad model and how

much of this free, internal data storage capacity is left inside of your iPad model?

I uploaded the latest IOS 12.5.2 on IPad Model 792X/B Now when trying to play Cookie Jam it will not load, I have turned it off but can’t play it.

Regards Lyn Jeffrey

Try a hard reset of your iPad by holding down both the Home and sleep/wake buttons simultaneously until your iPad goes to black and restarts with Apple logo, then release the buttons.

Good Luck!

Yes.

I already researched this in the iOS App Store.

The OP's iPad is running iOS 12.

That app should launch and run.

That is why I suggested the hard reset.