Why is my sis behaving like this with me?

this is going to be a long one plz do bare with me you do need to understand everything before you do suggest any course of action. i have this cousin of mine who has come down 4 work & has been staying with me for 4 years now. Up till recently i haven't hand any problems with her. It all started when we had a major misunderstanding between us which we just recently cleared & went back to normal or at least that's what i thought. she told me that she doesn't talk much , she likes having her space & all. That's fine with me cause even i am the same. but that doesn't mean that she doesn't talk to me at all. What i mean is that she wont initiate an conversation with me. She will talk to me yes. But only when i start / initiate. It's always me who has to do so. she is only like this with me. as with my parents she will initiate a conversation on her own. its only with me that she don't initiate a conversation. I know that she loves me like a bro , cares for me ,etc. But i don't know...at times it just hurts so much....at times i feel that she is just doing a big show. I am frustrated & angry but mainly frustrated cause before she used to initiate conversations with me. I want things to be like before. 1. Why is she acting like this with me ?? 2. Should i just ignore her ?? i don't understand i though we were clear. but its happening again.....its like an hydra....you take one head off 2 others will grow. 3. Why the hell me why can't i be in peace ?? 4. Is it only happening to me or even you have gone through this ?? 5. She told me if i have a problem with her i should talk to her directly but i don't. why is that ?? Its no use talking to my parents about it or even my other sisters they think its not that serious or anything. now don say that i should take it easy or that i am overacting or that i am in love with her or anything like that cause i know i am not. I only want things to be like before. pls do help. & plz do reply with the corresponding numbers to my questions. this is a serious matter....don't joke about it. i'd give an arm & a leg for things to be like before.