Bad call, as has been pointed out (...several times). She's irresponsible and reckless, with no skill or experience to justify it. (Rick and Shane are cops, and Dale knows how to handle guns.) The only thing that can be said about her behavior is that at least it's consistent for her character: Self-centered and unbalanced. Her selfish desire to prove herself competent and useful despite everybody else's justified reservations about her ability to handle a weapon ended up nearly killing Daryl.

(Line-by-line refutation in 3...2...1...)