@Jodec, your post #6 makes me think that your 3 in an AP -even though relevant- can be overcome by your 2 college classes (note that Oxford will take Y! of a US uni instead of APs). That’s as much b/c of the range of material you have covered on your own and the other indicators you give of a personwho really has spent a lot of time in their subject- and that matters a lot. Oxford is exhilarating (and exhausting) if you love your subject; it is only a slog (and exhausting!) if you do not.
The money part is relevant: you have to work out with your family whether you can afford it. If you can, and you found Balliol’s welcome letter fun (as my source did), I would recommend going for it.
Btw, your EU citizenship won’t help in the UK- in the past b/c you have to have been tax-resident to get the tuition break, and going forward b/c the UK won’t be in the EU…