@joel From an "old(er) person", this is 100% normal.
This is your first career job, and it's a very different dynamic from working a part time or seasonal job. You're still learning the culture and the people who make up that culture.
I started in a new school last August and I felt the same things - not really sure how to connect with people or start to share a little about myself without feeling pushy. I've found they're just as interested in getting to know me as I am to know them.