HELP!! ANYONE!!! PLEASE!!?

There is this girl in the grade below me who i have liked for several months. I do not share any classes with her other than homeroom, so i do not get to talk to her much. Recently, we were put in the same group for some school team building crap. She talked to me for the entire two hours. I was surprised, because she is a very shy person, as well as me. Although many of her friends were in the group, she primarily focused on me and only talked to them when they started a conversation. We had several short conversations, and she seemed interested in what i was saying. She brought up some seemingly insignificant stuff we did earlier in the year (i remembered them as well, because did them with her) She knew quite alot about me, my nicknames, where i was from (Serbia, and i was surprised again because nobody knows where that is) Then all of a sudden, she stopped talking to me after the team building thing. I guess her shyness kicked in, as well as mine. I really want to tell her i like her, but i do not know how. I am going to the high school next year, so i want to tell her before school ends. I do not know how. I am worried, because there are only 2 weeks left. If it helps to anyone, i go on a weekend trip the day that school ends. Can anyone tell me what to do? Does she like me based on what i described? (i think so, but that could just be my wishful thinking at work) Please, i really need help. PLEASE. I really like her.