Was it wrong of my teacher to say this?

Sorry if this is really long.

Basically, I just started back at school today and I had my first lesson in my new statistics class. I was feeling pretty positive about it, even when my teacher said that he had looked at some of the grades of the people in our class from last year and was going to talk to us individually about whether stats was right for them. I never imagined he would come talk to me in a million years; I took stats last year and got on pretty well; I passed, I didn't find it overly challenging and I only failed one assessment. however, my teacher went up to me part way through the lesson and told me that although I had gotten enough credits to get into stats this year, he felt that I hadn't gotten the credits from the right areas and I would probably struggle with stats this year, and may want to consider dropping out. I was really surprised, but I just sort of nodded and when he asked me if I was willing to work "really hard" I said yes.

It sounds silly, but I felt really upset about it afterwards. The stuff we were doing in class today is pretty much the same as we did last year, I got the credits I needed from stats and the school obviously thought I could do stats this year, as they put me in the class. My stats teacher from last year said she doesn't think I'll have a problem with stats this year and my mum got mad when I told her what my teacher said, saying he was "setting me up to fall" or something. So, was my teacher wrong, or was he just being honest?