I would change a few things to make it sound more natural. But first, I need to ask a few questions to be sure I know what you want to say:
(a) Do you live "inner city" or in an outer part of it?
(b) Does the library already exist, or is it yet to be built?
(c) Is the library "inner city" or in an outer part of it?
(d) When you say 'unimaginable', do you want to say the benefits of the library are (i) "hard to think of, but strong", or (ii) "easy to think of, and strong"?
(e) Are you talking about the city's children in general, or any specific children?