Got An Interview With The Help Of A 3rd Party Recruiter. Can you guys please help

Hi. I am a graduating senior. I found a full-time opportunity on a 3rd party recruiter website and felt that I am a good fit for the opportunity. So I reached out to the recruiter and had the first-round onsite interview with the firm on Wednesday.

Before the interview began, the HR told me that they will invite a few more candidates that week and the last candidate will come on Friday. She said she will reach out to me next Monday or Tuesday with regard to the final round interview.

The interview was pretty difficult because they gave me some technical/case questions that I was struggling. So I thought I did badly and had a little chance of getting the final round interview. And after the interview, the recruiter reached out to me and asked how the interview was and we had a short conversation. Surprisingly, the HR reached out to me yesterday (Friday) evening and said they want to invite me for the final round interivew.

I have like a week until the final round interview and want to be prepared as much as I can. I am wondering if there's another candidate for the position. I do not want to ask this to HR outright.. Instead, I want to talk to the recruiter and say "I really appreciate your help. I was able to get the interview with your help. Do you know if there's still another candidate?" Would that be a bad question to ask to the recruiter?