How long does it take to go into status epilepticus after stopping medications?

Varies. Could be a single dose or many doses. Not all patients with epilepsy will develop status epilepticus off meds, but anti-seizure meds should never be stopped suddenly.
Varies. Some patients with epilepsy can develop status epilepticus after missing a single dose of medications, for others it might take much longer. Not all patients with epilepsy will develop status epilepticus off medications, but one should never stop anti-seizure meds without discussing it with one's doctor.