When...

You know she's the only girl when...
She races into the room excited over a rope (or whip in her case)
She carries around a mini measuring tape as her prized possession
She suggests "wrestle time" throughout the day
She can spot a gun from a mile away
She can hold her own with phrases such as "Knock it off, Kid" or "Give me my space, Ev"
You tell her to "dance", and instead she squats, then attacks
Her baby loving can quickly be abandoned if there's a game of pillow fight going on
She asks to share the axe with her brother
She suggests a screwdriver when something breaks
She knows how to work everyone's soft spot and does it with incredible success