OS X El Capitan Reinstall

Hi, because of the new Mac update my system was not booting up so I lost all my data on my laptop and the system is reinstalling the older version OS X El Capitan. While installing it asked me that it would be verified by apple and hit ok. The system is downloading the OS but it's taking so much time to download as usual.. pls could you help me out as I know El Capitan is an out dated OS now.