Negotiation skills and buying a Used Car

I just bought a used Mini from the only dealer in Oregon (so not a lot of opportunity to comparison shop). The sales woman was about five feet tall, looked 18 (if that), was dressed in a hoodie and black jeans, and had a tattoo of a mini on her hip. (I don’t actually know about the tattoo.) It was absolutely the best negotiation ever. We drove the car, left the dealership, researched prices, and sent her a text with an offer based on blue book. Immediate reply: “I’ll check with my manager as soon as I finish with this customer.” Three hours later we got an offer letter at our price back from her, we signed, texted it back, called the finance guy with my SSN, and picked up the car with a 0.9% loan the next day. We might have left a few bucks on the table, but not many, according to the Blue Book. Oh, and Miss Turns-Out-to-be 24 (who has worked at the dealership since she was 18–for eight years) is the dealer’s top sales person. Yes, I asked how she’d ended up selling cars.