Is the receptionist flirting with me? Ok to ask her out?

[flitzanu]

one easier option...wait until your PT is over and you're no longer going to be a patient, and on your last day when you'll never have to be there again, consider asking her out. 

that way you don't have to face her every time you go in.

"hey its my last visit, i've really enjoyed seeing you blah blah, maybe i can take you out sometime"