I receive communion kneeling. I have never, as far as I can recall, had anyone complain about it, nor had anyone trip over me. The main thing, I think, would be to not cause a commotion, as has already been mentioned. If you are quick about it, the only complaint you could possibly receive would be from someone who doesn’t understand that you are trying to be more reverent, not trying to draw attention to yourself. In fact, I have noticed that more people have begun to receive kneeling at my parish—especially altar servers, since I, myself, am a server.