That's too young. I'm 16 and i have a 13 year old sister, she's ridiculously young compared to me in my eyes. I know it's all about maturity ect but a 13 year old hasn't had much time to mature. These kids are just starting to go out on their own, into town with mates ect. I'm far from asking mummy if it's okay if i can go town with a few friends for an hour... i'm almost 17 so i'm pretty close to the stage where i can go out into pubs and clubs and pretty much do what i like and i feel im mature enough to do that. 13 year olds are way off that maturity level, a lot of them have barely touch alcohol, with exceptions obviously. But my point is i feel theres a huge maturity difference and you may have experienced stuff a lot of people do on the way to 16 which she hasn't yet.

You can try and kid yourself telling yourself she looks older and acts older but really.. is she really as mature as you? Conversation wise too, not being offensive but education too.. your 3 years above here, thats pretty much the whole of senior school. Your going to be hugely more intelligent and more mature, unless either shes extremely smart or the other way around lol.

I just feel at this age, 3 years is too much. Theres too many differences no matter how many things you can say you have in common.

Plus if i was you i'd hope she doesn't have an older brother. Because i have a sister and i find theres a massive gap between us and if one of my mates even said anything out of place about her they'd know about it.. let alone mention sex in a serious way.

Don't take any of that the wrong way, don't wanna sound offensive or rude.. that's just the way i feel. Maybe she is really mature and maybe she is ready, mentally and physically.. then who am i to judge. But judging by the average 16 year old male and the average 13 year old girl.. you know..