I've found that even if someone has 2 pets the same level as you, and 1 pet a level higher, you will lose almost every single time, unless they make a mistake or you get extremely lucky and his attacks miss. That 1 level provides quite a punch.
It will balance itself out over time. I think more people are doing dailies, new heroics and raids, gearing up, professions, etc. before they start seriously doing pet battles. There will be a point in the near future where you will be 25/25/25 along with many others.
I'm also a bit worried because I've seen that the rarer pets do have an advantage over the more generic ones, due to the fact that I've seen some extremely powerful abilities from rare pets that surpass anything I have.
At any rate some types of pets have innate abilities that are much better than others. The Undead and Mechanical abilities to revive themselves after they die are f***ing amazing compared to some of the others.
Overall pet battles have some balance issues that need to be worked out and I have some faith in Blizzard to iron out some of the wrinkles.
Please change your vector and move to a different coordinate because this quadrant is off limits.