Crack one open and see if it is fertile. If it is, start saving them and when you get enough to set, give them to her. If she is a determined broody, setting an extra 2 weeks or so will not be a problem.
If you are concerned about smaller pullet eggs not being good to set, you can forget that, if fertile they will hatch fine. Smaller eggs make for smaller chicks, so when buying you should expect at least normal sized eggs. OEGB's are small anyway, and she will have no trouble raising small chicks.