I can never take doujins like this seriously. Probably because of the corny monologues.
That's kind of the charm of this one for me. Maru's really, really worked up over the classic teenager problems of sex and love, but she's read too much, and so she has a weird idea of what love is that the real thing apparently can't measure up to and she overthinks everything and turns her guilt into a corny monologue. Or at least, that's my interpretation of it.