Finding your element is a relatively new practice to the magical community, and is a somewhat altered form of astrological and alchemical-based magical practices of the ages past. But is it really necessary?
If you are seeking out your own specific element, I would first have you consider nature. Where do you ever find an element isolated, and by itself? Fire requires air and fuel (earth) to sustain its presence. Water, believe it or not, contains air (how else would fish get the oxygen they breathe through their gills?) and earth (the sediments it washes away), and is otherwise found in deep in the earth, in the clouds in the air, and in all living things. Earth is all around us, and almost never alone. The minerals that help sustain life. It changes as water washes it away, plants and animals grow or decay within it. It contains vast bodies of water and liquid deep in its bowels and flows like rivers when fire heats it enough. And air? Everywhere as all. The gasses within the earth. The fuel for fire. The breath in our lungs. The pockets of bubbles we see in rivers and seas. So on... So forth.
So then where do we begin to define yourself by your element? This was born of astrological practice, I believe, where various astrological signs are said to have influence over various elements.
The various signs of the Zodiac all generally have an element that pertains to them, or that they are said to influence, but then so too do planetary bodies, the moon, and the sun. In this, the way they interact will also vary. The time and location of your birth, and so forth, within astrology will provide more explicit details than your birth month alone. However, this also usually means that you'll find that you are influenced by more than one sign that each in turn have influence over more than one element due to the way they interact with one another.
This further reveals how the elements are almost never solitary, and how individuals do not "have" one element, or two, or three... They are part of all four. The element that you relate to the most is merely a psychological exercise, perhaps describing your personality and way of thinking far more than it explains your magical practice.
Granted, the way you think and your personality will have a great deal to do with the way you practice magic, as well.
But I must stress again that it is best not to limit yourself to a single element. Within old occult and alchemical magical traditions, each element is part of the whole.
Fire is considered pure and cleansing, it is the warmth within you and the passion that drives you. Water is the glue that holds it all together, sustaining life and giving rise to some mental aspects. Air is thought and breath and whim, and gives rise to imagination and creativity and so forth. Earth is what makes you solid, physically, mentally, and emotionally.
I paraphrase a bit, but this is how it works. If you find that you lack passion and drive, seek the balance of fire energies within your life. If you find that you are instable, and flippant, seeking grounding within Earth. If you need more spontaneity, seek the flippant nature of air. And if you need to tie it all together, or otherwise seek to mend, turn to Water.
Why stick to just one?
I would argue that I have not even encountered a spirit elemental in nature that could be wholly described as a single element, even if most of its attributes were of that element's qualities.