I don't think it's just wanting to make bad decisions because she can. I get Elizabeth because to my mind--and maybe it's just my fanon Elizabeth--she's struggling with some of the same things I do, only more so: trying to figure out what it means to be a woman and be a person who makes her own destiny at the same time. And Elizabeth's doing it from scratch (which I don't have to do) without having any good model for what that is--no mother, no female friends, nothing. It's no wonder she doesn't know what she wants...it hardly existed back then.