CosmicGamer
Mongoose
You can go from no skill to level 1 then 2 then 3 and so on. While it is possible to go from no skill to level 0, level 1 then 2 then 3 there are no instances I am aware of when you have to obtain a skill at level 0 before being capable of gaining level 1.
As I stated before, the only ways I'm aware of gaining level 0 are basic training and background skills. Sometimes methods whereby multiple skills are acquired at the same time instead of concentrating on one. I think of it as gaining ability to make sure you get the basics so you can get by but not training and education to become skilled at something.
In the learning skills section itself, level 0 is counted the same as no skill for the purposes of determining the number of skills you already have.
Basing the decision on the rules as a whole, the way I handle training is to go from no skill to level 1.
YMMV
As I stated before, the only ways I'm aware of gaining level 0 are basic training and background skills. Sometimes methods whereby multiple skills are acquired at the same time instead of concentrating on one. I think of it as gaining ability to make sure you get the basics so you can get by but not training and education to become skilled at something.
In the learning skills section itself, level 0 is counted the same as no skill for the purposes of determining the number of skills you already have.
Basing the decision on the rules as a whole, the way I handle training is to go from no skill to level 1.
YMMV