Is cremation okay for Christians?
No, it is not okay, for God created the body and saved it by the death of His Son. Desecrating the body by burning it in fire is the profane practice of pagan devil-worshippers with no knowledge of God (I Cor 6:13-20). Men in the Bible were buried, even at great cost and inconvenience, because their bodies sleep in the grave until the resurrection (Gen 23:1-20; 50:25-26; Deut 34:5-6; Matt 14:12; 27:57-60; Acts 7:60).
While God is easily able to put a body back together that has been cremated or destroyed accidentally or intentionally some other way, it is a sin against God and your body to treat it in such a disrespectful and pagan way. The wicked only will have their bodies burned in hell!
For much more about cremation and burial in the light of the Bible: Cremation.