Is plate heirloom wearable at lvl 1?

Is plate heirloom wearable at lvl 1, or do I have to reach the level to learn plate armor?

Yes, but prior to level 40, it is downgraded to a mail item.

Yes but if you give it to a level one it will be mail, and when u train plate at lv 40 it will become plate

Thanks a lot!!