Now you have all the info you need to help you decide what it means when she never texts first but always replies. She tells me she is seriously into me, but when she is busy or busy and with friends, I get completely ignored.
She has no time to text me, but has time to tweet or retweet tweets. Anyone please say it to my face, what is this. When she is with her friends, she is interested in maintaining that social relationship.
It is possible that she feels strong feelings for you. She may be interested in developing a relationship with you.