How do I establish a closer connection with my gf?

I have been dating my gf for 4 months now. She is 25, I am 22. We are 100 miles apart so we spend every weekend together. And by those standards the 4 months we have been together is really shorter since we don't see each other all that much. But we talk an awful lot during the week.
She has been in 2 four-year relationships and is a very romantic/relationshippy person. But after her last breakup (1.5 years ago) she became very independent and not so romantic anymore. In our first 3 months or so she began to become alot more mushy and intimate but when I reciprocated she got freaked out because she felt it was too much all of a sudden. Now we are okay again but it feels like even though these 4 months have only been spent on weekends, it feels like we should be more intimate/romantic by now. Or am I wrong? She is always kind of keeping things flat and neutral. Not too much intimacy and not too much distance. We have awesome sex, very passionate there. And she says it's the best she's ever had and is very attracted to me. So it's not a problem of attraction. We have awesome chemistry and alot in common.
I just don't understand what her jadedness is all about. Why is she so hesitant to let go and be more romantic? She says I'm the most compatible partner she's ever had but it feels like she has committment issues - even though she asked ME to be her bf in the first place!
Am I just jumping to conclusions? Is 4 months too soon to expect this? Especially with only weekend hangouts?

P.S. - I also realize this might be due to her age as she isn't some young 17 yr old who falls head over heels in a blink of an eye. Older people tend to be more logical in their relationships. But still!

Any ideas?

Four months of only weekend hangouts isn't enough time. It sounds like she doesn't really know why you are with her. The more uncertain she is, the more she will want to play it safe with her emotions and not get too attached or commited. You need to find some genuine ways on letting her know why she is the perfect match for you. You need to let her see why you want her and nobody else.