As Nerdy said, though, you must not let your fluff interfere with that of others.
The other Dragonborns in play do not actually have a tail so you can't go around saying that dragonborns usually do. Therefore it might be worthwile to have an explanation as to why your dragonborn does.
Subspecies? Deformity? Actually not descended from dragons but from the lesser drakes (and having a chip over his shoulder about it because drakes are just as proud and fierce as dragons!) etc.
It can actually be an interesting character quirk.
HEY HEY HEY NOW!!! Don't forget Warforged shaped like rocks! But, no, definitely, DEFINITELY no Dragonborn with tails!!![]()