As I'm a new player who is just getting into netrunner I was just reading the whole rotation of sets and was wondering about identity cards.

If the identity card comes from a data pack I believe it shall rotate out with its pack.

Confirmed.

But we are only in the 4th cycle. Won't rotations be a couple years out before we have to worry about them? This isn't MTG and that's a good thing!

If release cycles stay on schedule, it should be around spring of 2017 before the first rotation. Subsequent rotations will occur approximately every 12 months after the first rotation.

https://www.fantasyflightgames.com/en/news/2014/11/5/when-new-programs-overwrite-the-old/