Thematically speaking, a thesis that focuses on conformity and rebellion is very possible to do from the story "Two Kinds." The thing to remember about writing a thesis statement is that it is largely a statement of opinion. It is possible for you to write a thesis statement like the following:
"The story 'Two Kinds' shows the themes of conformity and rebellion."
The above statement is a statement of opinion about the story. In the body of your essay, you will need to prove to your readers where those themes are illustrated. Broadly speaking, Jing-mei is rebelling against her mother's wishes instead of conforming to them.
The previous thesis statement is manageable, but it is also really boring. I would recommend doing a thesis statement that is a two-part statement. That kind of thesis allows you to write about two sides of an issue. For example:
"Although conforming to Suyuan's wishes would have been difficult for Jing-mei, rebelling against her mother was a much more difficult action."
That thesis now allows you to focus on the themes of conformity and rebellion while also discussing the impacts that each action would have on the characters.