Can I get a 1-year student visa in Thailand when transitioning from a tourist visa?

okay, FIRST off when you go from a tourist visa or a visa exempt entry to a Non-Immigrant Type ED (or any type) visa inside the country you ONLY get 90 days.

Then you go back to the immigration office with more documentation from your university and they can give you an extension for up to a year (at their discretion), although many people only get 6 month or 90 day extensions for the first time.