It's dimensionally transcendental. Obviously it's bigger on the inside. It's a Type 40 Time And Relative Dimensions In Space TARDIS. Approximately 900 years old. Its chameleon circuit became dysfunctional sometime in the 60's, which explains it's obsolete police phone box disguise, and you haven't gotten around to fixing it. The way you hold yourself and the goofy smile on your face signifies that you're clearly trying to cover up your dark past, and considering the fact that you have two hearts, which is made obvious by the double pulse coming through your carotid, you're a time lord. The last of the time lords. Am I wrong?

I don't know. I notice.