I think Town is a great style for any age.
Normally, I'm a firm RH girl. However, I have a Canard Town in RGGH.
Like viewwing, I do think the RRGH on mine makes it looks a tiny bit more grown-up, which is why I purchased it - to provide a bit of variety with my other RH Towns. Plus, I thought the RRGH looked amazing against the Canard, whereas the RH looked a bit flat for my liking... however, I still wear it with my jeans, T's and boots, and I think it still looks nice.
My Black RH Town and Sang RH Town look really carefree with the tassels.
I think there maybe no "young/old" issue with these bags, rather more what you wear with them.
My grandmother, who's very trim, taut and absolutely un-enhanced terrific at 88, rocks her RH Black First, but when she wanted to get a Town, we thought she looked nicer getting a RGGH Town (because its a bit bigger on her frame - she's 40kg and stands about 155cm. Plus, she's really, really, fine-framed, so the tassels on the Town would overwhelm her look).