For the longest time, and still a bit til now, I never thought about it, you know, every teenager think they're matured, that they know everything, that they're smart and cunning, so they never thought of themselves as someone less.
That you realize this shows you have grown a lot.
People can usually tell when someone is less mature than them. A teenager will consider a pre-schooler a baby, and to an adult, they are both kids.
And also, the first steps was her wrong, but I believe I did more wrong in the time that we were together.
Why? I understand there are things you are not mentioning. That's good. Keeping quiet applies to the internet as well. But the wrong she has done weighs heavy, and it is difficult for me to believe you could have done anything worse.
That aside, the first steps matter. This is not about two kids throwing dirt at each other. In that case, you are right, it does not matter who started it. Both are equally to blame(, and their parents even more so for not teaching them any better). But consider this:
A teenager throws dirt at a toddler. The toddler throws dirt back, and the teenager is very unlucky: there's a stone in the dirt which injures his eye. Would you blame the toddler for taking the teenager's eye out?
Sure, you would scold them and tell them not to do it again, but they are a toddler. And they were following the lead of someone older, the teenager.
I know this is not a perfect equality. What you are implying is that the teenager threw dirt at the toddler, and the toddler then stabbed the teenager with a spade.
Can you see why I find that difficult to believe?
Regardless, it's not something anyone but you, her, your psychologists/lawyers/closest family members should be talking about. There are topics for gossip. Being an asshole is a topic for gossip. Two adults breaking up with one another can be a topic if they do so noisily and childishly. But bored acquaintances should not be sifting through other's dirty underwear, especially not years after. Keeping such rumours alive is malicious, and whatever explanation you give is simply fuel for the fire.
It is of a man's duty to be dumb, and a man's pride to be honest.
If you can stick to that pride, you are a good man. Though you will need to find a lady who can appreciate your honesty.
"Honey, did I gain weight."
"A little."
"..."
