Is my stake in safety until the release of NEM? I don't want to sell it or anything, but just want to be sure it's safe and it won't "burn out" because I didn't do something in time

You are fine.
However, rather than just waiting around for launch, why not try to actively help out the community? There is an open alpha from 06/25, so please test it out and give feedback. Also, talk about NEM to people you know. If you can code, create something cool. Ideas for a symbol/logo for NEM, post here:
https://bitcointalk.org/index.php?topic=640772.0Let's work to build NEM together.