How old were Sting and Rogue relative to the other Dragon Slayers at this key point in the timeline? So anyway, in the latest chapter, it was revealed that:


   Natsu and the 4 other Dragon Slayers from 400 years ago actually met some time before they were sent to the future. Quoting Zeref, most likely because of the dragons in their bodies making this stuff (I forgot the name) to prevent them from turning into dragons themselves, they have mostly forgotten about meeting.
 
 Before they time travelled, they all seemed the same age. And Lucy's mother opened the gateway (I assume) just once for them all. She didn't have all keys and became ill until she died, so I think we can definitely assume she didn't do it again.
 
 Then how is it that Sting &amp; Rogue are generally the same age as Natsu in the past, yet have to catch up to Natsu, Gajeel and Wendy who are frozen (petrified, Fairy Sphere'd) for 7 years?


I mean, it could be a reason we don't know yet. Or am I just missing something VERY simple?
Sting and Rogue are the same age as Wendy, in the manga the three are currently about "20" in the latest chapter (I am excluding the +400 years). If my memory serves right, Natsu &amp; Gajeel are both "27". 

Now the problem is working out the age different in the past, this isn't all to hard. Wendy was "12" when she was first introduced (x784). The Dragon Slayers arrived in (x777), so it's 12-7=5. Wendy was "5" years of age. Now Sting and Rogue are the same age as her, so those three were "5" years old. Now assuming I'm correct about Natsu's &amp; Gajeel's age, they would've been 12 at the time. 

Now I'm not sure if this answers the question, but I hope it does. Just keep in mind that Fairy Tail has a habit of making 12 year old kids look even younger than what they are. Easy way to tell is watch the Fairy Tail OVA 8.