My left eyebrow is higher than my right, what should I do? (Photo)

Given your youth, you may want to try Botox first to give your eyebrows a little more even appearance. If you like the look, I'd recommend proceeding with an eyebrow lift, which will last longer and ultimately cost less, as Botox must be reinjected every three to four months to maintain results.
If surgery is an option for you, at my center, we can perform a brow pexy or 1-mm brow lift under local anesthesia to give you a naturally alert and refreshed look.  The procedure can be performed bilaterally or unilaterally which seems to be what you’re looking for.  Local anesthesia means that you can be awake and help direct your final outcome by giving feedback on the look we are going for.  
Your first step is to find a board-certified facial plastic surgeon who can evaluate your brow droop and recommend the best corrective measure.
I hope this helps!

A common reason for eyebrow asymmetry is underling eyelid ptosis, so it is possible you have left upper eyelid ptosis, causing your left eyebrow to elevate to assist lift the droopy eyelid. See an oculoplastic surgeon for evaluation.

It is impossible to say from the photo provided but my best thought is that you have a bony asymmetry with the left side of your face (forehead here) larger and more convex than the right.  These asymmetries are common and not necessarily a problem.  Most attractive people have some feature that isn't perfectly symmetric. This could be adjusted on the operating table but my experience is that over time when there is an underlying bony difference the soft tissue (skin and brow) tend to revert to their original position.  You need to see someone if this bothers you to get an accurate diagnosis.