"You will be instructed"
"I have been taught for 4 years"
"You will [self-study?]"
"I have been [self-learning?] for 4 years"
Both seem kind of clumsy. Is there a better word or phrase?
An independent study is typically undertaken by a student who teaches himself or herself material with minimal help from a supervisor or instructor. (Wikipedia calls it an "educational activity undertaken by an individual with little to no supervision", which works here up to context.) Similar terms include a self-directed study or self-directed learning. Autodidacticism might also work, although that word is longer and perhaps less suited to all situations, as this question explores.
So you could write