I've been wanting to do this as well. But my dd has her own money so it wouldn't have anything to do with me per se other than potentially affecting my credit. I do wonder if she'll spend more or end up spending less. I think it's an important life lesson however, as we no longer live in a cash environment and they need to learn sometime. I'd rather her learn now, while still under my guidance, than when she's out of the house.
You are brave!!!!
My 16 yo dd has a debit card.
I would check with your bank before giving your dd an Debit card.