Body reunited with soul

Will the old body be united with the soul? I know we will have a glorified body in heaven.

On the Last Day the Lord will raise the bodies of all who have died (John 5:28-29). Bodies and souls will be reunited.

As you noted, God will transform and glorify the bodies of Christians. That will be true for Christians who died prior to the Last Day or who are alive on that day when the Lord returns visibly to this world (1 Corinthians 15:35-57; Philippians 3:21).