What do all these things mean?

I haven't had my first kiss yet, I never kiss my siblings, and once in awhile my parents will give me a kiss goodnight/goodbye. Recently at an after school activity of mine a pretty good friend of mine kissed me on the cheek. She was acting silly and hugged and kissed her sister. But then she did it to me! I'm not a lesbian but it was just so different and caught me off guard the girl (Jen) even told me I got red. she also told her friends, "I just kissed Sara (me)," jokingly. The funny thing is she denied her boyfriend to kissed her multiple times and then later they broke up I feel like something is different when I'm around her now even though to most people it's probably not a big deal. What should I think about this? Should I feel different around her? Thoughts?