Reddit mentions of The Oxford Handbook of Quaker Studies (Oxford Handbooks)

The Quakers: A Very Short Introduction can be read in a day. You could try to find The Oxford Handbook of Quaker Studies at your library for a more comprehensive introduction (I've only read the former).

I would tell you just to go in and expect silence and reflect on the silence. Most meetings aren't often religious, and will be completely open with you admitting your doubts or personal opinions because the point of worship isn't conversion and character shaping but self-searching. Talk with the community after worship ends, and just go your own way from there.