My (19m) newly ldr girlfriend (18f) says she doesn’t know me at all

Me and my girlfriend were doing wonderfully, and planning how to get over the hump of long distance (3 hour drive) while I’m in college but now that I’m here I’ve noticed a change.

It feels like in the past month I’ve been here my girlfriend and I have started growing apart. When I asked her about it, she admitted that she feels like she doesn't really know me. She said that I tend to change depending on her moods and that I never seem to disagree, take the lead, or communicate when something she does bothers me.

I understand what she means; this pattern has repeated in many of my relationships (platonic or otherwise) and ended more than a few, but I also wonder if it’s just the distance being new to us? She’s also started school back home and generally been more stressed than usual. I don’t feel like I’ve treated her any differently, but I can’t disregard that she feels that way.

I want to know how to make a permanent change and I've started therapy for partially unrelated reasons. Should I start disagreeing on small matters? Should I express opinions I know aren't entirely rational? How can I make my own thoughts and feelings apparent to her so she doesn’t feel like she’s dating someone she doesn’t know anymore?