Can I just rig my high poly model instead of having to retopologize it?

I’m creating a project for a class I am taking; it’s a character model. It’s pretty stylized, and I spent over a week working on it, and it’s due soon. Currently it’s at 180,000 Verts, 350,000 Faces, 370,000 Tris. How many hurdles would I run into trying to rig this model for animation?

I just started "Retopologizing" the model, and I can tell it’s going to be very time-consuming. I’d rather just attempt to rig the model as it currently is. I don’t really understand why it’s so difficult. If I’m careful, is it really that big of a deal? Tips and advice much appreciated.