My Student's Secret Pleasure

I'm a professor at a prestigious university, and I've always prided myself on my ability to maintain professional boundaries. But lately, something has changed. My student, Emma, she's in her twenties, but feels like someone much younger sometimes, confides in me about her secret desires. We began our relationship as mentor and mentee, nothing more than academic support. But over time, I've noticed a shift. She starts wearing more revealing clothes when coming to my office hours, and there's an undercurrent of tension whenever we're alone together. It wasn't until she whispered her secret that everything clicked into place. She confessed that she has fantasies about age-play and DDLG dynamics. The idea of being in a teacher-student relationship as adults isn't unusual, but the twist is that Emma wants me to act like her father, to guide her through life's challenges while also indulging in some playful role-playing on the side. We agreed to explore this further under strict guidelines, nothing sexual unless she initiates and consents fully. It started innocently enough: mock punishment for getting a poor grade (though I know she didn't try), bedtime stories, and even having her call me 'Daddy' when we're alone. But as our dynamic deepened, so did the intimacy. One night, after she performed beautifully on an assignment, I found myself unable to resist taking things further. She let out a quiet moan when I gently disciplined her for imaginary misbehaviors that were actually just creative writing prompts gone wrong. It felt... right. Now I'm struggling with whether this is crossing a line or if it's okay as long as everything remains consensual and she continues to set clear boundaries. Am I an asshole for indulging in these desires? Is this healthy, or should we find another way forward? I need advice. How do other people handle such intense but consensual dynamics without losing sight of professional decorum?