I recently had a client ask me for a contract agreement to sign... What do I do?

I have a lady who initially contacted me to House sit her dog while on vacation, I mentioned I wouldn't be able to do this because of my allergy to cats. She never responded and I put her request in the archive list. Last week she messaged me again, but this time asking if I could board her dog. We set up a meet and greet with our dogs and things went okay (her dog is a tad dominant, but nothing I haven't dealt with). She wanted to arrange a day for her dog to then come over without her for a couple hours. We agreed tomorrow would be the best (Thursday). However, she then proceeded to ask me for a written contract that I 'find off the internet'. She is a http://Rover.com pet owner. I do not feel comfortable being legally bound by something over the internet... Does Rover have anything I can send to her. She is quite pushy.