Help! Buying My First Project Car

It wouldn't hurt for you to get a bill of sale. I always do here in Texas when I buy a used car. Include the VIN, make and model and amount you paid for the car on the BOS. Get someone to sign the BOS to acknowledge that they did receive the money. I usually make two copies with my and the other person's signature so that we each have proof of the transaction. If she signed the title you should be good to go, at least that's how it works in Texas, we have to have a signed title by the owner (don't know how it works in OK???). Good luck, hope you got a good deal!!