I'm usually the one being tied up and I'm not generally fussy about whether they're a guy or a girl. However, if I'm the one doing the tying, I will only ever tie women.
I've only ever done bondage with people who are a similar age to me. Bondage is a very sexual thing for me, so it would be bizarre to do it with someone much older and just plain wrong to do it with someone much younger xD I've always been the youngest in my TUGs (always by less than a couple of years), but I wouldn't be opposed to doing them with someone who was slightly younger
