Here's the thing:
I absolutely and totally and unequivocally disagree with Joanne Rowling about the Hogwarts housing system.
If the people/wizards in the Harry Potter world are anything like the people in our world (and this is a valid assumption since even though Rowling makes no references to real life events in the books, she does present the wizarding world as something that exists in our world - for example, The Leaky Cauldron and Diagon Alley are located in the London of our world), they aren't just brave or hard-working or intelligent or ambitious. And sure, the three main characters have other characteristics than just bravery, so prominently indeed that it seems like they're all in the wrong house. So you could argue that Rowling meant that one of the four main attributes is more dominant than the others.
But I still disagree! In my humble opinion, you can be brave, hard-working, intelligent, and ambitious - all at once, in equal intensities, or in varying intensities, depending on the situation. Sometimes the situation demands more bravery than intelligence, sometimes more intelligence than ambitiousness.
So you're all of the attributes, all at once, at individual intensities.
I know I'm not very brave. But a couple weeks back, I caught myself spontaneously doing a courageous deed in defence of a loved one.
I know I'm not very hard-working. But I'll be damned if my laziness ever comes in the way of my success.
I'm fairly intelligent. That doesn't stop me from doing stupid things regularly.
And I'm ambitious - yet I procrastinate and sometimes think I might not deserve the things I dream of.
(Not to mention the gazillion other attributes more or less everyone has in varying intensities.)
But hey - maybe, maybe, if you just did something irreversible, you could become more brave. Or if you thought more about things, you'd become more intelligent. Or if you just sat down to work. Or set stellar goals and executionable plans.
Maybe you could choose your house - the individual house only you're in - that's an interesting mix of every attribute you have, in the intensities you choose.
It takes bravery to do it, though.