K, i think this girl might like me, but im not sure. Help pleease!?

K, first of all, im ftm trans, which means, basically, im a boy stuck in a girl body. i havent came out to anyone other than my mom and my sister, but they both just think im a , along with everyone else. i dress in men clothing, and i have short hair. K, so i have a friend, and both my mom and i think my friends sister might have a "thing" for me. I work with both of them. I recently took a car trip with my friend and her sister because we were supposed to go to place for halloween. after,we stayed the night at her house, which she owns with 5 other people. I found it a little odd that my friends sister asked me to go to this event, rather than my friend. Another time, my friends sister asked me if i wanted to come over for "pina coloda and movie night". She has a boyfriend, who was there, but i still found it odd that she invited me, rather than my friend. Another time, she asked me to come over to her parents house(where my friend lives) ever though neither my friends, or their parents would be there for quite some time. One day, when i was working, my mom went through her cash. afterwards, my mom said that she kept smiling at me. So, in your opinion, do you thinks she's just friendly, or she has a thing for me. My mom thinks she does, but im still left debating what i think.