I guess I should have also stated that in ANH - Luke & Leia are supposed to be 19 years old. Another three years pass between ANH and ESB so that makes them both 22 at the time of ESB. ROTJ supposedly only takes place 1 year after ESB so that means they would be 23 years old in ROTJ.
Han was 29 years old in ANH which means in ROTJ he's 33 - ten years older than Leia.
Even if Leia didn't have kids for ten years after ROTJ, it would still mean she had her first kid at 33 years old (Han would be 43). Last time I checked, women have kids that this age all the time w/o any problem whatsoever.
So setting the ST 30 years after ROTJ means that when they start, the ages of the main three characters are:
Luke - 53
Leia - 53
Han - 63
And the ages of the actors in 2015:
Mark Hamill - 64
Carrie Fisher - 59
Harrison Ford - 73
With the help of makeup and movie magic, I have no doubt that Hamill and Ford can be made to look like they're playing characters only a mere 10 years younger than their actual ages. Considering that in 1977, a 57 year old Obi-Wan Kenobi was portrayed by a 63 year old Alec Guiness and NO ONE seems to mind, I don't think another four years is that much of a stretch.
And Fisher is only 6 years older than Leia would be at the time, so again, not enough of an age difference to get so upset about.