How do you know if things are too intimate between you and your boss? My friends think she has a thing for me, but I never took it seriously until now

I always figured she was just informal, but lately there have been more flirtatious texts and "I miss you texts". It makes me a bit uncomfortable. She's my boss and atleast 20 years my senior, so the idea of a relationship would be very inappropriate. I've been trying to keep things professional, but she keeps pushing. Idk what to do...