My parents will not trust me!?

Today my parents went boat riding and left me at home with my sister and FRIEND Curt. They let us watch a movie (meet the robinsons btw) So we finish and my aunt invites us to a movie. parents say yes. We go and sit down at the movies. Curt(boy) sits by me. My aunt comes in(just off the phone with my mom, she saw curtis with us) and tells me my mom doesn't want curt sitting next to me. so he moves. Why is it that they let me be home, WITH NO ADULT SUPERVISION, with him, but then freak when he sits by me in the movies? When my parents get home i want to talk to them about this cuz i am tired of having to deal with the 'helikesyou-youlikehim' thing. What would be the mature thing to do? BTW I have never done anything that would lose my parents trust. I geuss you could say i am the good girl of the family. *sigh* Please help, i don't want to disrespect my parents.