How Old is Titan's surface?

Astrobiology Magazine's website has an article on how the two craters found by the Cassini RADAR team during the T3 flyby relate to the age of the surface. Here is the summary (take the last sentence with a grain of salt):

How old is Titan's surface? For years, Saturn's moon Titan was thought to have mastered the cosmetic surgery of the cosmos, with barely a mark or wrinkle to betray its true age. Close-up views provided by Cassini instruments show that Titan is nearly as flawless as it seems from a distance, with only two impact craters found so far. A world with a more youthful surface may be more likely to harbor life.

The problem with determining an age based on crater counts is that we don't know the production function for impactors in the Saturnian system (we don't even have a full grasp of it here in the inner solar system). In the inner solar system, we can rely on the moon as a crutch to determine ages, but without a late heavy bombardment in the outer solar system and with different populations of impactors, you can use that crutch in the outer solar system. Certainly the relative lack of craters on Titan compared to its peers in the Saturnian system can give us a relative age, certainly its surface, or at least the parts observed so far, are much younger than Rhea, but without even the slightest grasp of the production function or gravitational scaling (more craters will impact worlds closer to Saturn than away, ignore Iapetus) except for some rough estimates by Zahnle et al. (2004?), I don't think we can put an absolute age on the surface.