So theres this girl..?

shes a senior and ima sophmore..she had a cousin who liked my friend and i let them(my friend her cousin and her) come over so we could chill. well while the other two were outside, i was inside sitting in my kitchen and she comes and sits by me after she finishes talkin to my sis.she asked my was i texn a girl wen i was my friend tex me to let me noethat they were goin to the car..i told her and then she got me talkin bout what kinda girls i like..i told her how i dnt tend to date my age because i like mature girls, and she startd telln me bout how she stopped talkin to this guy..we tlk for a while then i walked her to the car and wrapped her arm in mine and gettin all flirty...this was three days ago. what should i do??