Like I said, rationally speaking, you're right, but mind-sets don't matter when you can analyze something rationally and follow your decision without difficulty. A mind-set comes into play when a problem is rationally intractable or emotionally vexed.
But that's not self-sacrifice by my definition, because you're still the one reaping the benefit. Getting up early to do work that will benefit someone else and not yourself - that is self-sacrifice. Getting up early to get ahead in your studies is just self-discipline.