Catch Me If You Can

In the studying area on the first floor, there were a guy and a girl studying together for a midterm.
The guy kept staring at the girl and they suddenly got eye-contacted.
Girl : "Something on my face?" with a smiling face.
Guy : "Nah...I just...think you always look pretty even though I don't even know your name..."
Girl : "Oh, I didn't tell you that yet? blah blah...you also look good."
Guy : "Thanks. I've been watching you for a while and still thinking the same."
She got blushed and when she knew about him, she suddenly looked blue.
Silence came over.
Guy : "Did I say something I shouldn't do?"
There was no reason why she couldn't hide her sad face,
but at somewhere in the middle of her heart,
where the guy could possibly transpass into,
for that little short time,
she realised she wasn't able to forget someone else.

When a guy who really loves you reminds the one you loved before...then, would you be able to fall in love with the new guy even though you're still not forgetting the last one?

I thought I could do and be over you.
but my heart cannot change.
I'm still the one who I used to be with you.
Why am I so stupid not gettin' over it?