worried about meeting my AAA offer for oxford

hiyaaa

so I got a conditional offer at Oxford to do languages in October. the offer is AAA and I do French, English lang/lit and Maths w Stats at A-level.

I have sat none of my exams or coursework yet apart from English coursework, which is 20% of my final grade. I've already done that coursework, and during that time I only aimed to get an A grade because I was 100% certain I would not get into Oxford and the offer of my 2nd choice uni was AAB. If I had known I was going to be accepted I would've definitely aimed for an A* in my coursework to provide a safety net, a kind of shoot-for-the-moon-land-among-the-stars kind of thing. Throughout doing my coursework, I frequently asked for advice for improvement on my coursework and followed my teachers' instructions accordingly; and on the 10th Jan (ecstatic as I was) I went to speak to them with the same worry, and they said that they would be surprised if I got a B in the coursework (teachers are not allowed to tell students what grade their work is at before its submitted). But what if I did get a B which drags down my final grade to a B?????

I am 100% going to put lots of effort into the other 80%, aiming for an A*, definitely! But I'm just worried I might miss an A grade because of my stupid lack of confidence before...

Am I overthinking? Put my mind at ease..
thanks x