This. I've played T and higher games when I was a pre-teen *gasp* and I'm pretty alright now. Nothing wrong with kids seeing nudity, violence, "advlt" language or whatever, it exists.
OP, I hope you settle it out, since I don't know how to help you. Unlike in other things, my parents are pretty ok with whichever games I play. I wish you well!
I find that the rating has more to do with the intended audience of the game rather than the appropriate minimum age someone could play. A lot like speed limits, I find most of the time, people actually go above the speed limit slightly because that is what the natural flow of traffic is.
Also, I first realized this when I got Rise of Nations for my 10th birthday. My dad was tentative about me playing a T rated game a 10, but after he saw what it was he didn't care. He made the comment that he thought it was rated T because he didn't think a little kid would be able to understand the mechanics rather than the actual violence being too inappropriate