[Junket]

There is a sticky thread at the top of the forum, hard to miss, at the very top, titled 'Open Sesame' that keeps track of which firmware versions have known jailbreaks. If your firmware is newer than cited there then you are out of luck for the moment, at least without doing a serial jailbreak.

Usually jailbreaks are easier with older firmware versions. So even if there is no current jailbreak for your device, you might want to keep it in airplane mode or otherwise try blocking updates to improve your chances.

c.f. IIRC, we haven't been able to downgrade since 5.8.8. So if you had older firmware than that, that could be an option. You won't be able to downgrade from 5.12, at least not in the normal manner, someone will have to figure out something creative to do so.