I am confused. The translation doesn't make sense. Is it 'go by yourselves to school' (ie go alone) or 'Take yourselves off to school' (ie command to go). I'm guessing it's a bit like using the verb 'irse' in Spanish if that means anything to anyone. Please can someone clarify? Also, this section desperately needs some notes. I rely on them a lot to look over before starting a section particularly when it involves grammar and Romanian grammar resources are scarce on the internet....
I believe pronouns like înșivă, însumi, etc. are called "pronouns of reinforcement." What they do is emphasize (reinforce) the identity of the person who is doing something. This is a bit different from normal reflexive pronouns, but it might be confusing because both reflexive and reinforcement pronouns translate to the same words in english (ourselves, myself, etc.). So, here are some examples of reinforcement pronouns being used in english:
"I heard that school was cancelled from the principal himself" (himself = reinforcement pronoun)
"John was too afraid to ask his mom for a ride, so I asked her myself" (myself = reinforcement pronoun)
"You know the name of this poem because you yourself wrote it" (yourself = reinforcement pronoun)
Hope that helps :)