>>513819134My mixed message is that you should have fun and try what you want to try while understanding that the build you play can matter quite a bit.
Try what you want because you learn the mechanics better that way. When something does go wrong, or when you can't get exactly what a build says to get, if you've played the class instead of being a meta-slave, you will have a much better sense of how to fix the problem. You'll understand how and when to make deviations from planners.
At the same time, following a build can really help smooth things out. Play around with necro, decide what feels good and what doesn't. Nothing wrong with taking your time to learn the game. There are no real penalties for failing in D4. The necro is very strong even without mythics. If at anytime you chose to follow a build, your character will really take off.