What to do with this girl...help!!!?

Hi, im an eighteen year old guy and I work at a movie theatre, a new girl was recently hired and I think she is very attractive… I flirted with her at work and she seemed to flirt back and say things like stop looking at my butt (flirty face) and you just cant concentrate while im back here can you (flirty face) and things along those lines that show that she likes me enough to at least flirt with me and joke around. There was an employee meeting and she sat by me during it then after asked me to go to coffee with her. We went to coffee and when we left I got her number and gave her mine and I said we should hang out tonight and she said maybe and she would txt me. She txted me saying she had work in morning and was reallyyy tired. So my question is what should I do next? I dont wanna see needy and so I dont wanna ask her to hang out again I think I need to wait for her to ask me? But if she doesnt ask how should I approach her for asking a second time? By the way we have only worked together like twice and so those to times and the coffee are the only times I have hung with her. So despite not knowing what to do next I still do feel pretty good that after only three times I have gotten her number and gone to coffee. Any advice is very appreciated.!!!