I was allowed to use calculators when I started algebra in seventh grade.

I found that calculators didn't help all that much once you got into symbolic stuff. They were useful for the final reductions, obviously, but for algebra the lion's share of the work is symbolic and at least the relatively cheap two-line TI calculator I was using couldn't do anything symbolic.

I know that there are calculators that can do Computer Algebra System stuff, and those probably should be held off on until at least calculus.