Why does this girl have to make life difficult for the two of us?

'k so at school theres this girl called Karla and these past few months i've noticed her more and more to the extent of really finding her attractive which is exceedingly rare for me as i am quite pessemistic arround this subject. anyway, i've never interacted with Karla she's in my English lesson the top set (so we are both very intelligent teenagers and as i was lead to believe, mature). Now, in English she sits in one corner and i in another so we've never talked in here either. yesterday i was moved into her math set (second to the top) and 'luckily' i was just in time for the new seating plan regeime and low and behold i was sat in between a boy called Liam and next to Karla when the teacher announced i was to sit next to her she said something along the lines of ''Oh no!'' so she really doesn't like me for no apparent reason and i've never interacted with here so i don't know why she barely even knows my name so why, i don't get it? Anyway through out the lesson she keped glancing at me and i back and then she would look at the board, it was a very awkward debacle. also, not meaning to sound arrogant but my English teacher keeps stating i'm possibly the 'brightest' kid in grade 10, is it possible karla feels intimidated in some way? she is also a 'popular' knid of person (you know the type) but the only difference is she doesn't obsess over the make-up antics. can anyone help me understand why she is acting like a moron and so pathetic when on the contrary, she's quite the opposite? Thanks, ten points best :)