"It is already morning, we are going to school."

Translation: Уже утро, мы идём в школу.

[voltsogen]

why "we are going" cant translate like "мы собираемся?"

[Shady_arc]

"собираться" means to plan/ to be going to do something. It is not about motion at all. And it requires a verb or an event to plan to go to.

Since "собираться" can also mean to pack up, "Мы собираемся в школу" means a completely different thing from what is suggested, i.e. either packing up your stuff before school, or making plans and arrangements to go there. Which are probably very similar.

[bright_flash]

"We are going (to do smth)" - "Мы собираемся (сделать что-то)". "We are going" where "are going" is Present Continuous, is translated as "идём".