Is age relevant/important for the Fairy Tail cast

[ShadowSJG]

Aside from obvious child characters such as Wendy, does age really matter for the main characters?
For example Lucy was 17 at the start and Gray 18 and Erza 19 but if they were say 21 22 and 23 would the plot change and all?

 

[Yunkers]

I don't think so. They do not behave according to their age anyway.
For me, I would like if anime characters (in general, not only in FT) were a little older. It is a little weird to see them running naked while being technically underage. (If I count correctly most of FT cast was 18 when the "Larcade thing" happened?)