I liked the idea that Janeway was in her mid - late 30's when she was thrown into the hind end of space. Sure, she had commanded at least 2 other ships before Voyager, but it wasn't like she had the experience of Picard, someone who'd been sitting in the center seat of the Enterprise itself for nearly a decade by the time Voyager was taken by the Caretaker.
I liked the idea that Janeway was a young, inexperienced Captain too.
Then, in season four's Revulsion, they told us that she finished her first command five years before getting Voyager (2365). (More precisely, that she first met Tuvok then, and has known him for "nine years", which offers a bit of wiggle room: perhaps it was more like 8 3/4, perhaps it was 2366.)
Still, that mission could have been for less than a year, and six years isn't a lot of experience for a Captain.
The rub is that, as I said, Riker was shown to be someone on a meteroic rise to command. Riker was first offered a command in 2364, so to have Janeway not be older than Riker seems .... insulting, somehow. It suggests that she was on a similar meteroic rise.
Jean-Luc Picard was 28 the first time he commanded a starship. William Riker was 29 when he was offered his first command. Data described either his own career or a typical one (possibly both)to Lore as "four years at the Academy, another three as ensign, ten or twelve on varied space duty in the lieutenant grades...". This strongly suggests that only exceptional officers rise to Lieutenant Commander before reaching 34 years old.
I would not be surprised to learn that Janeway commanded a ship when she was 35, but am bothered by the idea that she did it when she was 30: she never seemed like that kind of meteoric riser to me. And that puts her in her early 40s at the start of Voyager, because she finished her first command in 2365 (ish).
I forgive the actor being the "wrong" age a lot. Estelle Getty on Golden Girls isn't a great example because she was actually made up to look older than she was, but lots of actors play characters who are older than they are, and most of the actors playing high school kids on tv are in their 20s. (On That 70s Show, the male kids were all 20 in the first season except Fez who was 18 and Hyde who was 22. Donna was 18 and Jackie was 15, yet they were all playing 16 year olds. Foreman's sister who was away at college is played by an actress 8 years older than him.)
Sally Field did a movie where Tom Hanks was her romantic interest. In their next movie together, she was his mother.

(She is, actually, 10 years older than him.)
Heck, Picard was quite a bit older than Patrick Stewart.
As I said, for some reason it stuck me that Janeway was being made younger in an effort to stroke Mulgrew's ego. That's why it bothered me.
Maybe I'm just projecting Shatner onto her.
