I'd still suggest a resounding HELLS NO!
Even now that you have left the company, she can still file a suit for sexual harassment and/or unfair hiring practices and that suit will name you as one of the manager defendants in addition to the company. Your status as a manger makes you vulnerable and INDIVIDUALLY liable for any actions she believes are improper that happened while you were there, OR since you "met" her there, or subsequent to the interview, regardless of your current employment status.
Furthermore, your old company (in most states) cannot indemnify you for any adverse settlements or judgements, meaning they can't reimburse you for the money you may need to pay her. Finally, even if you prevail in a lawsuit, your reputation in your field will be trashed for many years, meaning your new firm may quietly let you go ("Sorry, Mr. Hobby, we're just adjusting the sales team structure...wink, wink. Don't let the door hit you in the ass on your way out. And this beefy security guard will ensure you find that door without stopping to see anyone else as you leave."), and you may not get hired by any new firms who will never divulge that they know you are "trouble."
Just stay away. Remember that on any given day, there are probably more than 1,000-2,000 women who just turned 18 years old in your state, or large city. It's not like you can't find dozens, if not hundreds, of fresh POT's to look at...
Is the allowance and sweet BCD time you may invest in her worth the risk of hundreds of thousands or millions of dollars you may need to pay from a court order? In other words, how hard do you want her to fuck you? :p
Life is good
The Cat