it's entirely possible for a low level alt to make a run through the crafting tiers until they reach supreme master.
if you plan on doing this as a weaponsmith, i certainly hope you have another character that can provide the necessary materials for this low level one. gathering the ore necessary to complete tier 6 will require one of two things: having another character with a high enough level to be able to access eregion and/or moria [where the khazad ore nodes are located] or having enough in-game coin to be able to purchase the raw ore that your low level can then smelt into ingots.
i did something similar with an explorer, a historian, and a woodsman. since i already have one KSM weaponsmith, i don't need two, so i haven't leveled my historian's weaponsmithing at all; but, he did make it to KSM scholar before hitting level 25 and it was through a lot of barter and scouring the AH to get what i needed.