It is normal to be unsure. Especially if they move schools, or start new subjects. I remember it took me almost near March to feel like I shouldn't drop A-level history and that I was really bad and stupid compared to the rest of the class, especially as we had a case of so many boys interrupting girls and just answering as if they had written a book on the topic and knew everything and weren't struggling at all. I felt that they were ahead of me (due to different GCSE topics even though A-level wasn't the same but their GCSE topics helped give more context to it). In reality I had the highest essays consistently and the boys constantly saying they were better didn't, but I didn't know that in lesson. I shouldn't have let then get to me or think I wasn't capable. I do History at degree now with politics.
It really makes be think of the butterfly effect (one random decision changing the whole trajectory of your life). For me it was in Y9 loving geography and planning to do it at GCSE, then a course counselling with the deputy head who told me I was better than geography and shouldn't limit myself and that I should do history as it's better (not that I think this, well I do think history is better), I was like I really don't enjoy it, he said I should and in the moment I said yes. No thought and I didn't want to at all, then basically the same for choosing it for A-level, I was going to do economics and my history GCSE teacher had been trying to get be to choose it for A-level but I didn't want to and didn't have a love for it. Then on the first day of GCSEs, I had R.E and after I randomly emailed the 6th form I applied to/was going to and said can I switch econ to history. Not that I was passionate, I still don't know why (mix of impulsiveness and relentless persuasion from my teacher I guess). I wasn't excited and thought it would be my '4th A-level' and I loved my other subjects so much more. Then had my third butterfly effect and woke up one day in y12 to y13 summer and thought,' How hard can it be? Boys do it' and realised history and politics was a thing. I wasn't even liking history that much at that point, I'd only recently in the last few lessons of y12 where we were learning coursework content, like the arguments about when militanism is justified etc and even though I didn't expect to enjoy coursework (our school choose the topic), I started liking it. In my personal statement I talked about how I hated history up till late KS4 (did some good, out-there topics, not many people do) and how I still didn't like it that much but then linked it to histograpgy and the rest. Anyways, long story short, don't let yourself think too much about other people and you're more capable than you think.