Brutal answer: no she was not flirting with you.
Giving you a smile and asking if you want to buy a t-shirt is not flirting. She is doing her job. Walk into a strip club and hot women will smile at you, wink, and ask if you want them to grind against your crotch. Guess what? They are not flirting; they are doing their job.
If she asked follow up questions like, "oh do you like that Cowboy's Jersey, because your from Dallas or because you have a body like a linebacker?" then that would be flirting.
Giving you a smile and asking if you want to buy a t-shirt is not flirting. She is doing her job. Walk into a strip club and hot women will smile at you, wink, and ask if you want them to grind against your crotch. Guess what? They are not flirting; they are doing their job.
If she asked follow up questions like, "oh do you like that Cowboy's Jersey, because your from Dallas or because you have a body like a linebacker?" then that would be flirting.