That seems fairly high, you can probably get a better rate.
I'm pretty sure student discounts stop after age 25 (the resulting decrease at that age though is probably much more than the student discount would be), but it depends on the company and state.
Try a GEICO quote. It takes a good 10 minutes to enter all of your info, but it's quick to compare coverage options once done. I pay $217/6 months for liability/property/uninsured. Now my coverage is little in comparison to yours (I only have the state mandated things, except at high amounts), but I did find that GEICO was by far the cheapest for me.