Bob isn't putting any pressure on her to be a woman. He's only vaguely polite to her until circumstances get them talking. His immediate question is, "How old are you?" (That is, you look kinda young, are you a minor?) And she promptly lies that she's nineteen when she's fifteen. He hasn't shown any romantic interest in her at all, this is her decision to start off their relationship on a false premise. And it's his fault?