Well before 2100.

I really think somewhere around 2035 with a huge error bar towards the next century. I think the first thing we think is AGI will probably be an expert system that is just really good at making us think it's an AGI. Like, it probably wouldn't be too hard to train an AI on near-present speculative fiction to get it to learn the right things to say. Combine that model with a few others (MuZero comes to mind, one of the image creation models, etc.), and it would probably be pretty convincing, but not actually do anything of its own volition.

A system that has human-level competencies in enough areas and a convincing amount of free will might take some more time.