I'd keep on reading it. It is funny and not enough has happened to figure wheter or not is is worth a read. Plus a couple more charatcers seem to need an introduction... Art-wise it's good and the expressions and background are really well done. There is not one dull panel.
--Everything below can be referenced to what was said in the previous comments.
I'm not sure yet that the manga treats homosexuality as an illness. (As 27raven said.) The only character so far who does treat it like that is the mother. However, she is depicted as irresponsible, coercive, bitchy and self-centered and we aren't positioned to take her opinion very seriously. There is obviously something wrong and small minded in how she is forces her child to conform to her views. I'm not sure if the mother's flaws will be dealt with but her sheer disregard of anyone but herself makes her quite a dislikable and repulsive character. But who knows - the mother may have more depth than she seems to now. (ch01 pg9)
So don't judge the manga quite yet. Her views aren't the heart of the manga.
As x0mbiec0rp said, it is unhealthy for the protagonist to want to faint and vomit in the mere prescence of males. Though she prefer girls, her aversion to boys is a bit too excessive as she completely refuses to interact with them. (Just sitting in the classroom - [thought] "Argh, damn you boys! Don't get close to me!")
We aren't positioned to completely support the main charatcer either - though she has the right values (eg. what she told Yui when talking about Yajin Hospital) and clearly isn't stupid, she is a little weak willed and she tends to avoid her problems. She too has some problems to deal with.
So beyond her orientation, I think (or I hope, at least) that we'll see some growth in her character at the school (despite how wrong it was of her mother to force such a thing onto her daughter).