Hi, I will be meeting a girl whose number I got recently. We started texting and she added me on facebook. I want to know what kind of things I can make fun of her about as I am not very good at conversations.

Here are some things about her:
she is a checkout chick
few days older than me
she thought i was alot younger than i actually am
studying IT, freshman
she works out
i know of 2 of her exes (i dont know them personally)

Personally I wouldn't bring up exes, it's either connected to negative emotions or makes her think about a special person that is not you.

You could use the few days older than me. I knew a girl 3 days older than me that I'd neg about her being too old for me in a serious tone but obviously sarcastic and playful.

You could ask her if her job is not too difficult for her, should give a good reaction given her studying IT (not easy at all afaik).

Also when the conversation dies down don't panic and try to find a different topic, just smile and look at her until something pops up or she starts talking again. Women like talking about themselves, but don't interrogate them.