philosopher-
Today we get married later because we want more out of marriage than years ago and we need to mature before we realize what with what kind of person we want to be married to.
You are presenting your speculation as fact. Who says this is the reason? I think you are ignoring a very simple possibility. In the olden days, no one went to school the way we did. They were taught whatever they were taught as young children, and your average Joe was earning a living by the time he was 10. And they weren’t working in offices either. In a society where children are on the street at such a young age, of course they will develop a sense of responsibility for their actions earlier. Surely they will be prepared for marriage earlier as well. Nowadays, kids have no life experience at that age, for they are still in school and everything they need is handed to them. Therefore although the halachic status of bar and bas mitzva may not change, I think it is highly unreasonable and naive to expect the same level of responsibility from a 12/13 year old of 2010 as one from the old world.
As for your ‘proofs’, I can only echo what SJS and rebetzin said. There are arguments to the contrary as well, and refutations to every point you’ve made, which demonstrate, at the very least, that there can possibly be other explanations. I am only debating with myself whether or not it is worth playing devil’s advocate here.
sof davar hakol nishma-
I agree that there is a concept of emunah. But emunah is precisely where there isn’t perfect evidence, and therefore I think it is a big mistake when people claim that they have ‘proof’ for these things, because their proofs are refutable and when they are refuted they diminish the value of the claim being made.