Lol, I felt so much second hand embarassment for the MC. I'm not even her, and I wanted to dig a hole and hide when she was pressured by the Blondie to elaborate on her feelings.
There are actually people(many indeed) that fall in love without noticing. Specially when it comes to lesbian relationships, since girls are far more closer to each other. Of course the same happens to boys, but society would be far less lenient in their judgment if two boys are seen being physically close and saying words of endearement.
Regardless, the point is that being interested in a person(in the MC case, Blondie) often makes someone approach them, and being counciously or uncounciously romantically interested on them is not different. In fact, there are many who only notice their same sex romantic feelings after a very specific and direct event happens; forcing them to analyse their emotions(for example, if one of two friends got engaged and ended up marrying someone from the opposite sex).
It was interesting in a way. I dont know if Blondie was merely trying to get things cleared between MC and her or if she actually wanted to know if a supposed crush liked her back(yeah, its a Yuri story, but I dont think they are quite mature yet to deal with what that means). Although, the way she was tactful and blushing would suggest she at least cares for the MC's well being, which its the complete opposite of what the Imbecile would do in her situation.