Long Distance Relationship Advice

So I met this girl on eharmony. The big downfall is that she is in Colorado, and I am in Oregon. I was open to long distance relationships because I live in an area where its hard to meet someone. Also I just wanted to connect with other females either for friendly chat, or to see where it ends up. When her and I met, we clicked, had great conversations. Then exchanged numbers and facebook information. We've texted and video chatted and hit off great. Now it appears that she is wanting to get serious. I told her that we would have to meet first before we can decide if we want to be in a relationship, and I have made it clear to her that I am not in a position to come down to Colorado and that she would have to come down here, which she may be open to. But she doesn't seem to understand what I mean when I say I want to go slow. She keeps asking me what I mean, or what going slow looks like to me, and I don't know how to keep simplifying it for her. She always wants to call or facetime with me every day, and there are times when I cannot. One - I work Graveyard shifts and so my schedule is different, Two - I have other responsibilities to tend to, Three - I cant think of much to say for a conversation every single day, and Four - Sometimes I just like to have my personal space, play with my dog, be with friends, family, do other activities. She keeps asking me questions that are too hard for me to explain or simplify. I am well aware that nobody is perfect, and no relationship is perfect. But I feel under pressure, and don't know what to do.