Houston police are sorting out the details after a shooting at celebrity pastor Joel Osteen’s megachurch on Sunday. Police say the female shooter was killed, and a young boy and a man were injured, reports KPRC. What we know: A woman holding a rifle and carrying a young boy entered Osteen’s Lakewood Church about 2pm and opened fire, say police. CNN reports that an off-duty Houston police officer and an off-duty agent with the Texas Alcoholic Beverage Commission returned fire and fatally struck the woman.The AP reports that the 5-year-old boy who was being carried by the woman was critically in…