Is it the right time? Any help appreciated.

I have been talking to this girl for almost 6 months since July. We have spoken on the phone 2-3 times and the last one was in October. Now we communicate mostly through facebook emails and a few text messages. I live about 5 hours (drive) away and little less than 2 months ago I drove all the way to meet her for dinner and some drinks. We had dinner in a nice moderately priced restaurant and 2 of her friends later joined us in the bar for drinks. We have exchanged emails and text messages after that 2-3 times a week. But in the last 3 weeks, I am getting mixed signals from her. 3 and half weeks ago, I texted and asked if she wanted to talk on the phone and she said she was really busy that week and she was going on a vacation the next week. So I replied...ok. we can talk after you are back. There was no reply for that. I knew she was back from her vacation and 3 days later on the 25th I sent her a text just wishing her merry christmas and nothing else. No reply for that either. She has been constantly posting things (2-3 times a day) on facebook during this time. I dont know what to think about this and confused. Why this sudden change. Or am I just being impatient. She seems to be a good person and I like her and would definitely like to pursue further. I am also up for the drive to see her again.

Is it the right time to ask her what she thinks about the situation. I am planning to send her an email and ask her if she wants to pursue further. I wanted to see what you people think about this. Any information would be greatly appreciated. Thanks.