Elinor does 'gush' a little about Edward in Ch. 4 and it gives us a glimpse into how they have been getting to know each other in this passage:

He and I have been at times thrown a good deal together, while you have been wholly engrossed on the most affectionate principle by my mother. I have seen a great deal of him, have studied his sentiments and heard his opinion on subjects of literature and taste; and, upon the whole, I venture to pronounce that his mind is well-informed, his enjoyment of books exceedingly great, his imagination lively, his observation just and correct, and his taste delicate and pure.

It sounds like they have been spending a lot of time together talking about books and drawing and world events and even some more entertaining topics that would allow 'imagination' to enter into it. Elinor also speaks of his sense, his goodness, and his excellence of understanding.