How about you set a deadline for 3 years from now (sooner if she initiates but only to the extent that she initiates). In three years from now, if she hasn't shown any interest in recreating a friendship and closer relationship with you, sure, ask her out on a date.
Adinva 51, S20, S18 M24 total 6/15/11-12/1/12 From IDLY to H moving out 9/15/15-3/7/17 From negotiating SA to final D at age 50 5/8/17-now: New relationship with an old friend __ Happiness is a warm puppy.