I don't know your girlfriend, but speaking for my self personally, I'm not always one to
think to open up. I've been in relationships were the guy would tell me he didn't feel like he knew me, and I was like "well what do you want to know? ask away"
If she's already told you she's a closed person, she maybe like me, and just not think to open up and tell you things. So if you want to know something, try asking first.
