[Solved] Potions Apprentice

I'm working on the background for my character, who is a Potions maker/master.  Is their guide for how long an apprenticeship in Potions would last?  I'm guessing about four years, but I want a second opinion on it.

I don't think we have a guide but if you work out that Severus Snape was able to be employed as a Potions Master at age 21, I would say 2 or 3 years might be enough if you are bright and dedicated enough.  I'm actually planning on making Luciana an Apprentice in Herbology and Potion Making, and would probably give her 3 or 4 years? Idk xD

That's what I thought because I remembered Severus Snape was a Potions Master at 21.  Thank you, consider this solved.