First off, Petsmart only sells male small mammals. I know this because I work there.
Unless they told you otherwise, little Marzipan is a boy!
I've had my first chin for about 6 months and he was the same way. But, in the wild they use their swiftness and reflexes to get away from predators, so your chin is just on high alert in case of danger. Eventually he'll warm up to you and realize you aren't a threat. But until then you have to be patient.
What I did when I first got mine was open the cage and stick my hands out like a platform and let my chin climb onto my hands, sort of as a trust excercise. Basically saying, if you want to get out and play, you have to trust me. It worked way better than I thought, and now my boy walks right onto my hands without hesitation.. Cause he knows then only way to play is to get through me! lol
Another thing, if you let him have free reign of the room before you try to bond with him, it may be harder for him to get used to you. Try to bond with him as much as you can before you start letting him out to play. If you aren't doing so, he'll get the mentality "i dont have to trust her, shes going to let me out anyway". And you definitely dont want that.
When youre in the room hes in, try and talk a lot to him. In a sweet voice, so he gets used to your sound. When I walk in the room and start talking to mine, he perks up and runs right to the doors of the cage cause he knows hes about to get out and play.
All in all, its a process. Dont get discouraged that he isn't warming up to you right away. I was like that up until recently. I swore up and down he didn't like me until I started noticing I was being able to pet him, rub his belly, and have him come sit in my lap without darting off. You will have little marzipan for up to 15 years, trust that yall's relationship will get much better. You get out of it as much as you put into it!
Good luck to you!