It will probably be an unpopular opinion, but Andrea was completely wrong for doing what she did.
Andrea kept talking like Dale was so wrong to make her decision for her, blah blah blah. Then, says, she came to terms with her situation, found her niche, and essentially a reason for her to fight to live. More or less, she took control, and no longer felt helpless b/c she learned to shoot.
If Dale hadn't stepped in, she never would have found out she had a will to live. Essentially, she did the exact opposite of what proved to be best for her.
Also, she made a decision she had no right to make. Sure she felt everyone has the right to make their own decision, but someone closer to the girl has more a right to say "keep an eye on her, make sure she doesn't hurt herself", than Andrea does saying "let's see what happens". That'd be like a stranger coming into a hospital room, where your loved one is on life support and saying, "lets pull the plug, it's what they would have wanted".