If I understand correctly, this is the 4 week boot camp challenge?
Which is the compressed basic training of the Army Reserve, as in you will actually be joining up to the Army Reserve. If you do not plan to serve in the reserves this is not for you. Since you will be a fully enrolled recruit, you'll then be put on the nominal roll of your local Army Reserve unit to attend drill nights, training weekends and annual camp, After you have completed phase 2 training that is.
That is, if what you are referring to is what I am thinking of.
Have you ever given any thought to joining the Army Reserve previously? Your parents are correct in their argument, but the Army does not want or need people who have no interest in being there. If you are actually interested in joining the Army Reserve, feel free to ask any questions in the Armed Forces section of the forum, or if you like you can PM me.
If you have considered the Reserves would you want to join as a ranker (which is what the challenge is aimed at) or do you have the qualifications/ability/desire to commission to become an officer?
Your first action in real life should be to make a phone call to your local Army Reserve unit, or pop into your local Armed Forces Careers office, where you get a good explanation of all the roles and trades offered to members of the Army reserve as well as someone trained to answer any questions you might have.