-Then, you have 15-day grace period if you inform your International Student Office. Talk to your school.
You may file status change from F-1 to F-2 before the I-20 expires. The problem is that if your spouse H-1 is approved before your F-2 approval, your F-2 application will be denied. Even if you file H-4 together with your spouse H-1 during the F-2 pending, your H-4 will be denied if the H-1 is approved during the F-2 pending. Thus, you just go to China to get the H-4 visa to come back.