Might there be a distinction between having to bare responsibility and outstripping your elders in practical thinking?

What I mean is that Elinor, while her father lived, may have had a relatively care-free youth; she may not have needed to manage the family's financial affairs, etc. However, her nature had her outstrip her mother in practicality/sense quickly, so that she did not feel that her mother was the person she would go to for advice (although she may feel deference to her).

To illustrate my point, in the extreme, we have Mrs Bennet whose judgement is not very good. As Jasmine has also pointeed out, the two eldest Bennet girls looked to one another and to themselves for advice, where they knew that seeking it from their mother would be unsatisfactory/insufficient.

While Mrs Dashwood is not nearly like Mrs Bennet, she does seem to let her romantic sensibilities run away with her, so much so that her decisions aren't always the wisest.

So acutely did Mrs. Dashwood feel this ungracious behaviour, and so earnestly did she despise her daughter-in-law for it, that, on the arrival of the latter, she would have quitted the house for ever, had not the entreaty of her eldest girl induced her first to reflect on the propriety of going, and her own tender love for all her three children determined her afterwards to stay, and for their sakes avoid a breach with their brother. Chp 1