I just turned 20 and still look like im 15, i grow a bit of facial hair and its mainly more on the neck. my penis size is 4.5 inches, voice hasnt change and i feel like i havent been growing for the past 5 years. am i going thru delayed puberty?

Puberty isn't the same for everyone. Look at your family members. Are you physically like them? You probably are like someone in your family. Puberty ends for most boys around 14-17 years. You have already been through that so don't expect more growth. Like each person we have to learn to deal with what we have and make the most of it. I apologize if this information disappoints you.

The end of puberty has an accepted marker if you are interested enough to invest in it. A single x-ray of your wrist/hand can be assessed for growth centers. If they are closed you are finished, open you are not.

In addition to the tests recommended to see if your growth plates are still visible, I would go to your physician who may refer you to an endocrinologists for a detailed physical examination and, possibly, based on those findings, for tests to make sure your sex hormone levels are appropriate and/or respond appropriately to stimulation, and/or the appropriate organs respond to those hormones.