Will this change things?

My girlfriend bought me almost $900 dollars worth of photography equipment. Actually, just a really expensive camera and tripod for my birthday. I don't have this kind of money and due to our age difference and where we are financially in our lives, she knows this. I went and bought the camera on her credit card today (she was on phone telling me to buy it). Is this bad? I almost feel guilty, like it was too much money. She does a LOT for me. Should I return it? She said it was up to me.