£450 and i am 23 with Admiral, obviously you need to take into account much more than age...
Try this: Go through confused.com and put the policy start date 30 days in advance, i imagine Admiral will come up top, you can then go directly through to Admirals website from confused and you have to enter a few final details before you pay, one of these is the policy start date. At this point the quote is produced so changing the date to the actual one doesn't change the price.
Last year this saved me £78....