I unwittingly set up a meeting with an army recruiter and I'm not interested. How do I say no?

He called my house, asked me my plans and what I was interested in, and I told him communications/media studies, he said that the army has jobs like that and schooling stuff. the thing is, I was told by some of my relatives (who were/are in the military) that I wouldn't be cut out for it, and advised me not to do it. And when the army recruiter asked if I was interested I said "yeah, it could be an option". So he set up a meeting with me TOMORROW. for me to ask questions, etc. It sounds like it'd be a good opportunity but I don't know how I feel about the physical aspect of it, my dad who was in the National guard said that training was grueling. If it turns out to be something i don't want to do, what should I say or do?