At 21 you're still a high risk driver. When you get to 25 you're generally considered to be more of a medium risk. Just keep looking for good deals come renewal time, and build up those no claims, that's the most important thing.
I started off at 19 with a Hyundai Accent 1.3, paying £700 a year FTPT, that was on the Isle of Man, you can't get much safer than that. Now I'm 26 and am still paying £700 a year, but for a Golf 1.8 turbo fully comp in Manchester, one of the highest insurance areas in the country. The difference is 8 years no claims