Unwavering interest (obsession) with one person

As much I as I want to experience a relationship and love, I was unable to remotely imagine a specific person I’d share that with until recently. Growing up I had fleeting, superficial crushes that never went past “oh she’s kind of cute” but now for the first time in my adult life I’ve realized what real interest feels like. We shared a class last semester and beyond being my type looks-wise it felt like she was the first woman to ever give me the time of day, thing is we maybe spoke 3-4 times total so you can see how low my standards are in that respect lol. I almost (emphasis on almost) felt like I had a chance, I began to overthink all of our small interactions and the times where she was nice to me or I felt she was looking at me. What got was her approaching me after class to ask a question. It was related to class which makes my overthinking sound stupid (it probably is) but I couldn’t get the lingering thought that she could’ve literally asked anyone else. It was kind of a dumb question that she could’ve just checked the syllabus for or again asked the professor or someone else. Obviously my head wants to go to “she was looking for an excuse to talk to me and was using that question as an opening” and given all of the other signs I’ve sensed I really want to think so, but then again it’s almost certainly delusion. This would make her the first woman to have ever been interested in me and if it hadn’t happened before in my 23 years of living why would it happen now and so late? Again this was last semester and I haven’t seen her since, and as far as I’m aware I’ll probably never see her again. I wish I could get her out of my head but I cannot, I‘ve built her up in my head so much that I find it difficult to find other women attractive (or at least nearly as attractive).