light compression can tame some peaks, but using a peak limiter can help keep your tone cleaner and input levels higher.
When you record digitally, the hotter the input signal, the better resolution you get. It'll make your job easier in the long run. That's where compression is most crucial - before you run it to disk. Then when you get it in there, adding light compression to smooth your envelope or fatten your tone can be applied a lot more liberally.
But you really just need to keep your signal hot without clipping. If your gear sounds great to begin with that's all you really have to worry about if you can be sure to run a hot signal free from clipping.
You shouldn't have to worry about garageband or your interface working properly ever if you follow that approach.