Buyer doesn’t want to visit house?

I (FSBO) have a buyer (also no realtor) who lives in a different state that made an offer on my house without visiting it. We talked on the phone a few times and it sounds like a woman in her 60s. This all happened in the space of 48 hours.

She sent me a pre-approval letter from WF and the mortgage lender is real. She’s asked me some questions about the house (age of appliances, garage, etc) but has only seen pictures online. We haggled a little (I went down $5k on price and said I’d leave washer and dryer).

Is this a scam? What questions should I ask to verify if this is real or fake? TIA