What does it mean if a girl calls you big boy?

I was having a conversationg with a girl from work, i like her (has a bf) and i was asking her if she was working, tells me her time, aks me if im working 6-12 (generally when i work) i said nope 5-12 actually and she replies with Oh Big Boy now.
What does it mean if a girl calls you big boy?
Post Opinion