smear tests

I have recently found out that women do not get called up for a smear test to detect cervical cancer until the age of 25! Personally i think this is ridiculous, so i decided to find out more about this by going to my GP and talking to my nurse, she informed me that this is correct but it is due to the fact that women at the age of 25 and below have cells that are immature, so a lot of smear tests can come back abnormal even when they dont have cervical cancer. To understand why it has come back abnormal women are then sent to get a biopsie, which is a very invasive procedure and has been known to leave damage in the cervix and can possibly leave women infertile.
I do understand why the NHS has changed the age limit, however I do believe that women should still be able to request a smear test if they want one, even if they are not experiencing any symptons!