While I would echo what is said above, I would make it a little stronger and a little harsher toward what Edna rebels against, and add the sexual aspect of her resolve.
Much of what Edna experiences and attempts to do is motivated by an awakening of her awareness of the flesh. The sexual aspects are central to this, of course, but even her learning to swim is partly sensual, the feeling of the water on her skin, that kind of thing. Long dormant desires awaken and are part of her resolve to accomplish self-determination. This awareness leads to her withholding sex from her husband, which further demonstrates the connection between sex and her awakening.
And one shouldn't look lightly at the forces that lead Edna to rebel: society, the public, her husband, the double standard for men and women when it comes to sexual relations. Edna's resolve is to overcome all of these and determine her own present and future.
Unfortunately, she fails, and rather than go back to her old way of life she chooses to commit suicide in a final, fatal act of self-determination.