Do I Have Ptosis or Just "Hooded Lids?"

I don't see any pictures with this question which would make it easier to answer. That being said, in general you need to look at the upper third of the face as a whole. Your issue could be brow ptosis, lid psuedo-ptosis, or true ptosis. At your young age the chance of brow ptosis is less though I have seen it in young individuals as an inherited feature. Psuedoptosis is hooding of the upper lid where the lid margin(area with the lashes) is in a normal position. True ptosis involves a problem with the deeper muscles of the eye causing the lid margin itself to drop down in an abnormal position. Both problems can cause visual field impairment. Again, photos would help in diagnosis.

Hooding refers to the amount of skin on your lids, and when significant it can sit on and over the lashes. Ptosis refers to a droopy lid, which refers to where the edge of the upper lid sits against the eyeball. A normal lid sits at or just below the top of the iris such that no white shows above the colored part of the eye.

We'd best be able to give you an answer from a photo, but here are a couple of clues: If you can pinch a lot of shkin, and in lifting it off your lids your eyes look nice and open, then you most likely have just hooding. If when you lift the skin up you still see that your lid margin is close to your pupil (the black center in the middle of the colored part of your eye), then you may actually have some ptosis. Either way, both can be addressed with eyelid surgery.