Christopher Nolan's got a history with weird sound issues in his films.
Most notably was The Dark Knight Rises and how you more or less couldn't understand half of what Bane was saying. We have a theory on that. Wanna hear it?
The fact you can't understand what he's saying makes him more scary. Think about it. Someone who looks like Bane comes up to you, all angry and stuff, and mumbles something unintelligible at you, you're gonna be scared. Right? So it's the same with Bane.
Nolan has explained that he approaches sound in an "impressionistic way", stating that the film's sound mix was "adventurous and creative".
We personally would have gone with "WHAT'S THAT I CAN'T HEAR YOU OVER THE SOUND OF THIS ROCKET TAKING OFF AND HANS ZIMMER."
Nolan went on, saying that he visited several theatres incognito and checked out the sound mix to make sure it was coming across as he intended.
Some audience members have complained to cinemas about the sound mix, claiming that dialogue in certain scenes are barely audible whilst other sound effects are overpowering.
Nolan, however, has praised cinema projectionists for presenting his film's sound as he intended, saying that something different like Interstellar is bound to "catch people off guard, but hopefully people can appreciate it for the experience it's intended to be."
So there you have it - turns out it wasn't just you. Nolan INTENDED to deafen you with that rocket scene at the start.