She should know.
The excuse always given is "Oh she can't handle it."
Yet look at all the **** she's been through the last few years. The Red Goblin, being saved by Otto, running FEAST, teaming with Otto, freaking CANCER.
That excuse doesn't fly anymore. Especially since they've hinted that she's known quite a few times.
Hell, even JONAH knows nowadays. And it's advanced their dynamic/bond.
No excuse to keep it from her.