Yes, ask her to stay after the seminar

With her presentation finished and all questions of her classmates answered she returns to her place while you go in front of the group. When you arrive at the front of the group you ask them if they have any questions. As there aren't any questions you only praise them for their good work during this day and wish them good luck with their test. "Wilhelmine could you stay awhile longer after the lesson, I have a few things I want to talk to you about you." you add at the end of your coclusion of the day. Wilhelmine agrees to stay awhile longer and you think you can see a slight blush on her face. After the last of your schoolmates left you sit down with Wilhelmine at one of the desks. "Hey Wilhelmine, I recognized that you are attending all of my seminars, while you ace all of the classes and you would clearly overtake most of your classmates in the next few months if you keep this up. From my point of view you don't really need to attend my seminars. Heck, if I'm going to say it the drastic way you are wasting precious Free Time visiting my seminars you could better spend with friends, family or people you love. So please tell me, why are you visiting my seminar?", you ask her.

Her first to reaction to this question is blushing furiously then she started stuttering: "S-So you recognized. H-How do I explain this best?"

You look her in the eyes, trying to soothe her with your gaze, but the only thing you seem to achieve is to make her blush harder. 'Damn, she is really cute blushing like that. You could almost directly fall in love with her seeing her like this', you think.

"I started visiting your seminars because I thought you were really nice and pretty, and over the time visiting your seminar I developed a big crush on you", she continues silently, getting quiter and quiter until she is almost whispering. "Since I already confessed this to you know, I can't loose anything at this point. So would you go on a date with me next Saturday?"

Now you are stunned, since you would never have guessed that this would be the reason why she visited your seminars and that she actually asked you out on a date after you confronted her so bluntly about it.