China?

A friend of mine has asked me to prayerfully consider joining his team (currently of about 5 members) that will be going to China for two to three years. They would be enrolled at a university as full time students learning to speak Manderin, while bearing witness to Jesus.
I told him that I would prayerfully consider joining his team, and at this point feel that God is probably not leading me that way, but I’m not sure. If you think of it, ask that God would give me clear direction and wisdom in this matter.