The reason why car insurance for under 21’s is likely to be higher is simply because they are the demographic that is most likely to be involved in a road traffic accident. Male drivers are a staggering 10 times more likely to be seriously injured, or worse, when they are under 21. The increased risk that young drivers place themselves and other drivers in when they are under 21 means car insurance is more likely to be needed more frequently and is therefore more expensive.
To ensure you are getting the best deal for your situation you may also wish to get quotes from a price comparison website - See below: