My kids aren't that old but speaking from a "it wasn't that long ago I was that age" and having teenage nieces and nephews point of view I think it really depends on the person.

I just don't think you can generalise it and say having older friends is good or bad. I think the best indicator is the changes in the younger person. I definitely had some older people lead me astray but then I also had some older people ground me again.

As for my oldest nephew him seems to have grown up a bit in the last 6months since changing friends (most of them are older) which is good news because he was very close to going off the rails. But with my eldest niece it's a very different story. I think they are being a very bad influence on her, she's become a real little trouble maker since hanging out with some older girls/boys in her street.

Glad to hear it seems to be positive for your son though