The choice of words for the first passage may be a bit problematic: You mention two regrets, and the reader may assume that "firstly" and "secondly" apply to thesee.
The setting could stand to be clearer. We can tell she's at Pemberly, but we can't tell when. Is shortly after the wedding? Shortly before? Years later? The "four months married" would do a lot more good early on in the piece.
Author's response
I am content to trust people to read carefully and to resign myself on occasions they do not.
As for the timeline, it isn't really necessary to understand the piece. Nothing hinges upon the reader knowing the specific date, and one is likely to assume that it takes place not long after Elizabeth and Darcy's marriage if Lady Catherine is still upset about the marriage as was mentioned early on.