There are no 3 adjectives that describe a person completely and fully. When asked to pick 3 and only 3 to encapsulate your entire being, the answer given is always in the here and now - what seems most applicable and appropriate at this very moment in your life.
Knowing that the top 3 adjectives for me can and will change as time passes, what strikes me as most relevant now are:
honest. resilient. impulsive.
It will be an interesting self-discovery to see where the trajectory of my 3 adjectives goes at different stages of life. i.e. I remember when I first moved to LA, they were: happy, energetic, and impulsive. These adjectives still describe me well, but over a year later, what's now at the forefront is a different set of 3.
It's always been my belief that to strive to know oneself more deeply is essential to making oneself happier in the long-run. And this 3-adj. assessment is a good litmus indicator of self-discovery and in the journey toward self-improvement.