Why not put her to work in a nuc and when you need her she will be ready.
This is almost what I did. I moved the existing queen from the hive to a nuc with a frame full of bees. I figured that may be enough to be viable, but even if it isn't, they will keep her alive.
I plan to move the new queen in tomorrow in a JZ cage. This way, I have the old queen to fall back on if there is a problem. Plus, there is a chance that the old queen can build up the nuc to a viable hive and I will have gotten two hives from the swarm.