It is too young and as Sirzy says, will this be on their medical records? As far as I am aware, pharmacists don't have access to patient's medical records so they have no idea of the history of that patient and the GP has no idea that the child is on the pill.
It doesn't prevent STIs and to be honest it sends out a very clear message that girls and girls alone are responsible for their own contraception whereas boys can just fuck who they like without a care in the world.
The pill gave me severe depression, something that wasn't mentioned as a side effect when it was prescribed. Will the pharmacists go through all the side effects with the children? Will they tell them that if you have sickness and diarrhoea that you need to take extra precautions?
Why don't they just lower the legal age to 13? After all, they seem to be wanting to encourage young girls to be able to get contraception without their parents or GPs knowledge so why not go that step further eh? Or why don't they, and this is just a thought, have a huge review of sex education in schools because if young girls are still getting pregnant then obviously something is not working and throwing the pill at them does not solve the problem, it merely tackles the side effects.
Young girls of 13 should not be having sex and I would wonder at their maturity to give their consent. You have to take into account abuse and coercion and you also have to look at WHY they feel the need to have sex at such a young age. You can't just say, "well we know that these children are having sex, we don't want them to breed so we'll just give them the pill" without looking at the wider issue.
As usual, our society just seems to want to bury its head in the sand as to what is really happening and just hopes that by tackling the side issues the problem will go away.