If you were to go random I would think the opposite would be a better idea. Personally, as a college student in his early 20's, I don't know what I would write or how well I relate to someone who is in his or her 30's or 40's. I feel it would be more rewarding if it were with someone of my own age, though not necessarily my own gender mind you. I also feel like since the average age on a site like Hubski tends to skew low there may not be enough older candidates to match up with young ones. So basically I think I now support a systematic system based on pairing people of the same age, irrespective of gender.
Aye, and I imagine that Hubski's population - which is probably heavily male - would not allow for sorting based on gender either.
I too am a 21 year old college student, which is why I like the idea of the pairing. I think that there are a surprising amount of elder Hubskinites. Even if someone in their 30s-40s were to correspond with someone like us, I think that that'd be fairly rewarding as well.
Well that's just my two cents. Whatever you decide to do I'll still be glad to participate.