Elizabeth qualifies her statement later on in the same discussion to make it clear she is referring to minor matters.

But in general and ordinary cases between friend and friend, where one of them is desired by the other to change a resolution of no very great moment, should you think ill of that person for complying with the desire, without waiting to be argued into it?" [Emphasis mine] (chpt 10)

I see no signs that Elizabeth regards matrimony as a matter of no very great moment - her reactions to Charlotte's statements and actions on this point argue she believes exactly the opposite.