The journey to Mecca is made because it is the fifth pillar of Islam.
It is also because Mecca is where the house of God is, as well as
two mountains and the Arafat Plain, all of wich represent very much
in this religion
This is the sole purpose of making this pilgramage, although
everything to do with Hajj will become more clear later on
The pilgrimage to Mecca is made late in the month of Hajj, hence the name.
If you know that you are not going to make it, then it is not worth trying.
The reason that it must be made in this month is because of many things
that the Prophet Mohammed, peace be upon him, did when he was around.
Again, everything will become clear once you have read the guide