Wasn’t she not paralyzed in the time in between killing joke coming out and getting announced to be canon?
The Killing Joke was assumed to be in canon the second it came out. While Moore may have toyed with it being non-canon, all other DC writers assumed it had been in continuity and treated it accordingly.
If it was definitely canon when in first came out. It was the whole reason Barbra became Oracle.
It’s canon but miraculously she healed and became Batgirl again. Her healing took place just prior to her new 52 issue 1.
Pre-New52: As far as I know, Batgirl retired shortly before Killing Joke, Killing Joke happened, Death in the Family happened (Barbara was in a wheel chair at the funeral), and then Barbara became Oracle in Suicide Squad. Barbara was still in the wheelchair as of Convergence: Nightwing/Oracle (2015). I believe she regained the ability to wiggle her toes in Birds of Prey after she had surgery to remove Brainiac bits (or something), although I’m not sure if that’s referenced again. Also, she sometimes had a digital avatar that could move around cyberspace.
New52/Rebirth: Barbara had experimental surgery that fused a neural implant at the base of her brain and connected to her lower spine (below the damage from the bullet). The implant allows her to use her legs. The new52/Rebirth Batgirl books mention the implant and sometimes use it as a plot device (e.g. she shorts it out, losing her mobility).
More to the point, even as Death in the family started I remember that when Joker escaped in the beginning of that arc, Gordon Mentioned alerting the League and the Titans to which Batman said “Good. Everyone’s going to want a piece of him after what he did to Barbara.”