At this point you're invested in scale. It's not ideal, but sometimes you have to take the less ideal sitch to keep yourself alive in the early game. Keep the scale and give the plate to your ghost.
For reference, +7 plate would block 7-45 damage. +7 scale blocks 7-36. It's not great, but it's not terrible either. You will suffer later, but only relatively in comparison to if you had been more patient with your plate. OTOH, presumably you dumped scrolls to keep yourself alive to get yourself to the point where you can now regret the choice. You can definitely ascend with scale. Don't worry about it.