In the "real world", scientists are saying that the first 150 year old person
is alive today... So, by the mid 22nd century you'll start seeing some people living that long. What does that mean for the average age? Maybe it'll be up into the 90's or low 100's by then.
This is of course assuming present trends continue. But I have a feeling medical science is going to give a few more boosts to longevity in the coming years. Heck, in 20 more years, people will be growing spare replacement organs! Assuming surgical costs have come down enough, organs that are deemed less than 50% efficient will probably be replaced with healthy younger versions derived from a person's own cells (meaning no rejection issues). However, the brain... that's another story. Imagine a whole bunch of 100+ people living out their lives in a catatonic or near vegetable state. That's not exactly the utopia I'd expect humans to strive for.
But who knows, perhaps in 30 years we'll have medical nanobots able to comb through our bodies, correcting defective DNA and revitalizing organs/arteries that are aging, enabling those who can afford it to live up to 200 years or more (before too much decay makes it's impractical to continue rejuvenation efforts).