My co worker wants to take back her hours after I’ve been working on her shift for about a year and a half already. ?

So - you traded shifts but now she wants to trade back.

Unless it was listed as a "temporary" trade, you will likely be the one with the choice of what YOU want to do.  I think your supervisor will take your side.

You can argue your point about not wanting to accept trading back.  You can argue that you wouldn't have done this if you knew it was temporary and not permanent.  If you have children, you can even argue the point of needing to make new arrangements for child care.  Remain calm when making your points.

If your co-worker ends up angry with you - that is her problem.

Time will tell.  I'm not psychic and you should not waste a moment worrying about it.  Your worry won't change a thing except to make you miserable.

Her shift? What job and what is she doing..is she working somewhere else?  Is it because of the shît corona?

How did she give u her hours? She she actually say here u can have my hours. Or did the manager put her to work somewhere else and is putting other people where she WOULD NORMALLY work? If that is the case than she has a right to be angry especially if it was actually temporary.

People do not need to say that it is "temporary" coz everyone needs to think that of course it probably is.

Did u only say "No" or did u say other things aswell. She has another reason to be angry as saying only no as an answer is really rude!

Well it is best to talk things out and see if things can be worked out.

It depends what is said from her point but also yours so maybe manager will see both points of view.