@ager - Gwen's from Earth 65. In that universe Parker is her best friend. He's the one that dies in her flashback.
In 616, where the older Peter B. Parker is from, Gwen was also the same age as him. Or at least she was until Amazing Spider-Man #121. They make no mention of her as being an ex-girlfriend of Parker's in this universe, because on the one hand it's unnecessary exposition and would confuse the GA and on the other hand would be really creepy to have an underage girl and a 40 year old man have that connection.

There was that scene in the movie where Parker is emotionally confusing the younger Mary Jane with the MJ from his universe and Gwen tells him that she knows what he's going through. She knows because she's going through the same thing with him, she's just keeping it to herself (because, y'know... creepy).

The main universe in the movie is Earth 1610 and although it is not the same as the old Earth 1610 from the comics, it does share some similarities and in the original 1610 Peter and Gwen were the same age and Miles was only a few years younger. In that universe Peter died whilst still a teenager, not when he was 26, like Chris Pine's Spider-man in the movie.
If the new 1610 does have a Gwen I would guess that she is also in her late 20s.


So yeah that's a really long way of saying that Pete and Gwen are the same age in their respective universes, but that the Gwen in this movie is from a different reality to all the Spider-men in the movie.

@ager - the same reason Peter B Parker is older than the Peter from Miles’ universe, the universes aren’t in synch space/time is all warped by the generator Gwen got sent into last week so the rules of space time are just all over the place they could have gotten pulled from any point and showed up at any time

@azimiq - Must've been a TASM continuation at one point.