You should share this with her, as she most likely already senses your fear. Start by letting her read this.

If you don’t tell her, then your relationship will likely fall. You may extend it for some time as a co-parent , but that will be harmful in the long haul.

I would imagine that even if she decides to exit she might still be helpful as a compassionate friend. Personally, in your place, I would accept that.

While fear is understandable and not abnormal, I don’t think any symptoms here is terminal. You will work through is as you will. And as long as you own your journey, then you will have the respect and help and love of others.

I am no expert, so just take this opinion with a grain of salt.
Good Luck !