Chong007,
boot into Recovery mode by holding down ⌘R as your MacBook Pro starts up. When the OS X Utilities menu appears on your desktop, select Utilities from your menu bar, and from there select Terminal. In Terminal, run the following command:
resetpassword
Follow its instructions, and your administrative user’s password will be changed accordingly. Exit Terminal, then select Restart from the Apple menu to reboot into normal mode. When the login screen appears, log in as your administrative user, and then reset your administrative user’s password keychain so that it won’t constantly ask you for your administrative user’s password when you need to do administrative tasks.
If you find that your administrative user is still parentally managed, you could reboot into Single User mode, and enter the following commands there:
/sbin/mount -uw /
/bin/rm -f /var/db/.AppleSetupDone
/sbin/reboot
These should allow you to create a new administrative user, from which you should be able to reset your original administrative user to a non-managed state.