20 years old, seriously considering an Upper Blepharoplasty

You do have mild right upper eyelid ptosis and you may also have mild upper eyelid ptosis on the left side.  It requires a very detailed assessment of an oculoplastic surgeon.  Should you have surgery?  It very much depends on your examination.  Small degrees of ptosis may be improved or not.  The surgery has limited accuracy.  How will you feel if the eyelid is under or over corrected?  These are perhaps the biggest risks for you.  Seek out a fellowship trained oculoplastic surgeon.  The American Society for Ophthalmic Plastic and Reconstructive Surgery (ASOPRS) maintains a geographic directory on their website to help you find a well qualified surgeon.  To this I would add that you also want someone who is aesthetically oriented-easier said than done.

Your right upper eyelid is slightly droopy (ptosis). Although ptosis surgery (not upper blepharoplasty) can lift the droopy eyelid, it may be worth it in your case. Best to see an oculopolastic surgeon for in person evaluation.