I agree with you in loving this - I didn't know that this was possibly the first passage of this type in English literature - which makes it even more breathtaking.

What I have always found impressive about it is the realism of the mea culpa scene. JA doesn't just write a straightforward "oh, I was wrong", sack-cloth and ashes scenes, nor a straightout case of denial, instead we still see Emma's pride coming through, and also a basic honesty:
after raving a little about the seeming incongruity of gentle manners and a conceited head, Emma was obliged in common honesty to stop and admit that her own behaviour to him had been so complaisant and obliging, so full of courtesy and attention, as (supposing her real motive unperceived) might warrant a man of ordinary observation and delicacy, like Mr. Elton, in fancying himself a very decided favourite. (chpt 16)