No, it was the first. She set Snape's robes on fire during Harry's first Quidditch match when Quirrel was hexing his broom and Hermione believed it was Snape.
Oh, you’re right. I was thinking it was in the second year when Dobby was hexing the bludger and was thinking she thought it was snape. Yeah, it was first year because he caught it in his mouth because of it.