I'm currently reading Well of Loneliness by Radclyffe Hall. Jaimie posted a great review, so I won't rehash the basic plot. It was published in 1928, and the first half has been Stephen's (yes a female) experience not knowing "what" she is, but sensing that she is something very different from other girls. The scene after her mother discovers what is going on with Stephen and Angela is so very sad, but ultimately a "scene" that continues to play out in the households of many LGBT youth 90 years after the book's publication.
I have also gotten the impression, at least from the beginning of the novel, that Stephen might not just be a lesbian, but perhaps transgendered. It's not that she simply is different, and likes boyish things, but it is mentioned again and again that she wants to be a boy. Is that a common experience among gay youth?
The book is slow going, but I'm enjoying so far, and looking forward to the rest.