Every member of my immediate family and my family of origin who has attained that age had taken algebra I, or its equivalent, by the age of 12, some under the old US system, and some under the integrated international system on which CC is based. The youngest was about seven or eight, I think. Median age, ten.
No noticeable issues with doing so for any of us. All of the post-collegiate family members acquired further education in STEM fields. In the case of our children, nipping perfectionism in the bud was exactly the reason we did it for one of them.
I would agree that the readiness of the individual by far trumps age.
