Alya Sometimes Hides Her Feelings In Russian - Chapter 5 I'm Not Really a Loner, You Know 3

Зампредседателя школьного совета would be completely translated as “vice president of student council”. Зампредседателя is a shortened version of заместитель председателя. Председатель would mean president here, while заместитель would be “replacer” if I were to be crudely literal. The verb заместить means “to replace” while the тель part adds meaning of “the one who does it” like “er” in “builder”.
Подруга детства would mean [female] childhood friend
Here, подруга is “[female] friend”, while детства can be translated like “of childhood”.
Я знаю means literally “I know”, Я meaning “I” and знаю meaning [I] know.
But next we have a weird mistake.
Да я.
Look, Да means yes, Я means I. If you put it together, you will get “Yes I”.
Meaning that was supposed to be here was “Even I can tell”, so I think it was supposed to be “Даже я”, meaning “Even I [do that/ am that/ etc. ]”
So, if we put the corrected version together we will get “I know. Even I know.” Which in Russian, as you can tell now, will be “Я знаю. Даже я…”. Note that Russian speakers don’t really like using Я before verbs since verbs can imply first person’s perspective, so it could actually be shortened to “Знаю. Даже я…”