If people keep going quiet when you walk in, it might not be about them.

One room going quiet means nothing. A pattern is worth a look, and looking does not mean assuming the worst about yourself. Sometimes the reason is dull: you are close to a teacher, or you repeated something once, or people think you disapprove of a thing they do. Sometimes it really is them, and the difference matters enough to find out rather than guess.

If this keeps happening, ask one person you trust and ask plainly. Something like: is there a reason people go quiet around me. Listen without defending, and if the answer is nothing, you can stop carrying the question around.