hmmm..many things can be possible in this case.

my first thought is that maybe she isn't allowed to go out with other guys....maybe you guys can meet somewhere with a group of friends...

second thought is that maybe that you guys are together now you feel like you don't have to try...maybe you think that you already know enough about eachother...try learning new things, her passions, dreams, interests and stuff. try to get in her emotional side...

third...the one you don't want to hear...maybe she lost interest...but if you do like her a lo, don't jump into conclusions like this one suggestion and try the others..

hope this helped somewhat! goodluck!