how can i get 64 bit update on my mac book air? Or is it too old of a computer?

Those warning are for 32 bit apps you have installed your Mac. If you are getting those warning your MBA is 64 bit and running a 64 bit version of macOS.

When Catalina is released in the fall and you upgrade any 32 bit apps will stop working. Apple is provided this warning now so that you can either delete any of the 32 bit apps you no longer use or upgrade to the new 64 bit version of the ones you need.

If you do not upgrade to Catalina, the 32 bit apps will continue to work.

I find your comment where you say 'both 32 & 64 bit Apps in 10.15' not run and then follow that with '64 bit Apps' only will run.

It appears you are saying it will not run and it will run 64 bits. I find that confusing. I think that you should not have the first '64 bit' in your statement and it would be much clearer.

Allan has you covered, Apple will be removing the ability to run both 32 & 64 bit Apps in 10.15, 10.15 will only run 64 bit Apps.

Yep, poor choice of words... maybe Both should've been bolded. :)

I was thinking maybe dropping the first mention of 64 bit.

Maybe 32 bit OR 64 bit? :)

OK. That is better.

I wonder if lbelgiano followed any of that.

We both hope so. :)

Haven't heard much of anything from him.