34 on ACT is as good as 36 for most colleges (congratulations on your success on your first try!).
Taking it again might look like being obsessed with the scores.
Still want to better your score? Take April ACT with a minimal prep prior to it.
Just analyze your December ACT thoroughly.
If you have not ordered its copy, you still can do that and receive it within ~5 weeks.
http://www.actstudent.org/scores/release.html
If you want to pursue NM (congratulations again!) - take the SAT in March and register for June just in case.