Can I repair the cracked screen myself or that not recommended?

Check out this link for a tear down of the display assembly: MacBook Pro Retina Display Teardown

Also check out this youtube video: https://www.youtube.com/watch?v=h5MLalnT...

As for changing the cracked glass... It can be done, and after looking at the teardown and the video you can determine whether this is something you want to do. I couldn't find a supply of only the glass, but if you want to attempt this, then maybe you'll have better luck. You can always buy a used display, and salvage the glass from it.

The other option is to replace the entire display assembly. You can buy that from ifixit: MacBook Pro 13" Retina (Late 2012-Early 2013) Display Assembly, and use this guide: MacBook Pro 13" Retina Display Late 2012 Display Assembly Replacement