Guild Wars 2

I was wondering if it’s possible to infuse jewels in the forge that already have agony resistance added to the infusion slot?
I know I would probably loose the infusion in the slot, but atm I have no essence at all to make the ring infused, so it would be nice if I could do it later.
Does anyone have any experience with this?

Yes, you can still upgrade it.
Yes, you will lose the slotted infusion, which you can replace.