A good thesis statement should make some argumentative claim about the text. It should be a statement for which you can provide ample textual evidence but with which someone could, theoretically, argue; in other words, it cannot be a fact. It could even point toward a theme or whatever the text is saying about its subject.

You might ask yourself a number of questions to get started: For example, what is the relationship of the speaker to the "girl"? To me, the primary speaker seems older, like a mother or aunt. Why does she speak to the "girl" the way she does? Is it out of love or something else? To this end, you might argue that the speaker's list of jobs for the titular "girl" comes from a loving place so that the "girl" knows how to survive and achieve some measure of happiness in her life. You would then need to find evidence to support this and explain why, even though she can sound somewhat mean, the dominant speaker is trying to be helpful.

You might also ask what kind of society the "girl" and the primary speaker live in that would necessitate this kind of an education. Does this strike you as a community where women have the same opportunities as men? Not to me, especially because the "girl" is only instructed how to "iron [her] father's khaki shirt so that it doesn't have a crease" and how to "iron [her] father's khaki pants so that they don't have a crease." She doesn't get to wear the professional, working-man's khakis herself. Thus, you might argue that the kinds of domestic instructions given to the "girl" make it clear that women are expected to keep the home and mind the children and that they have little opportunity to do anything else with their lives.

Finally, you might notice that the primary speaker repeatedly warns the "girl" against becoming a "slut." It seems, then, that this is the type of society that bases a woman's value on her sexual history and reputation. The speaker seems not to even believe the "girl" when she insists on her own virtue. The final line seems to make it clear that reputation is everything, and a woman's reputation is built on her sexual status.