I think the age of consent should be 9
Why do you think the age of consent should be 9.
I know that the child is not that mature physically speaking but mentally he or she can be more than capable to do that.
Even though you might think so, children are still not mentally mature. They still need a lot of growing up so that they can make good decisions. So their maturity in both body and mind is still not there to consent to sex.
I'm not doing anything wrong. The child's maturity is the key in deciding when a child can have sex.
But that is the thing even if a child acts mature, they are not, so they cannot make the decision to have sex with all their ability. It is better to consider that and think about the potential consequences for having sex with a child which could be serious.