As per the creation Chapters ,God created heaven, earth and man ,but there nothing to suggest that the heaven was created to accommodate man.God changed the plan when Adam committed the original sin ? If so ,was it not indeed a very substantial and crucial change in His plan of creation of man ?
The catechism says “God put us in the world to know, to love, and to serve him, and so to come to paradise” (CCC#1721). This is what the Baltimore Catechism says too, namely, Why did God make you? God made me to know him, to love him, and to serve him in this world, and to be happy with him forever in heaven.
The end of every human being is the beatific vision which is heaven, the paradise of which the CCC#1721 speaks of, union with God and sharing in his divine life and beatitude forever. This end is the only one that can fully satisfy the heart and deepest longings for happiness of every human being and angel too. As St Augustine said ‘our hearts are restless until they rest in Thee.’
The Church teaches that God created Adam and Eve with the original gift of holiness and justice which among other gifts included sanctifying grace which is a participation in the divine nature and the divine life. This sanctifying grace which human beings possess on earth is the seed as it were of eternal life, heavenly glory, the beatific vision. It is already a participation in eternal life which the full flowering of or development of is the beatific vision or heaven. So, the end for which God created Adam and Eve as well as of all their descendants, all other human beings, is the beatific vision which is heaven, seeing God face to face and being happy with him forever.
It is commonly taught that if Adam and Eve had kept the commandment God them to not eat of the fruit of the tree of the knowledge of good and evil, after their time of probation on earth, they would have been transported body and soul to heaven probably much like the ascension of Jesus into heaven after his resurrection and the assumption of the Blessed Virgin Mary body and soul to heaven. Jesus opened the gates of heaven by his passion, death, resurrection, and ascension into heaven. The gates of heaven were closed by the fall of Adam and Eve. This is symbolized in Genesis I think where God banished Adam and Eve from the Garden of Eden and set before the entrance to the garden the cherubim to guard the way to the tree of life. As the CCC says as well, God placing Adam and Eve in the garden of paradise is a sign of their familiarity with God, that is, sanctifying grace which is a participation in the divine life. Their banishment from the Garden is a sign that they lost this gift of sanctifying grace through their sin of disobedience.