So what are the chances percentage wise that I will hit 6'0 before I turn 21?

I'm 19 and I'm about 5'11. (I need to see the doctor and find out for sure) My father is 6'5, my second oldest brother is 6'5 and my oldest is shorter than me so I'd say 5'9-5'10 (not really sure on him)

You can't really help how you grow in height but I've been told eating habits can play a role in it. I really want to peak at 6'0 even...

Am I done for good?

Kind of a wive's tale really, but fairly accurate... If you take you height on your second birthday and double it, it's generally pretty close to how tall you will be as a full grown adult. Aside from that, I'm not sure you can really tell. You may ask your father if late growth is common in your family. My dad grew 4" after he was 23. It's all genetic that way.

Adult height is reached, on average, at 17.5 years old. But it isn't rare to have a late growth spurt.

It looks to me that your dad and second oldest brother have "tall genes" whereas you and your older brother have the short genes, so you could be done. Just wait it out and either way, be happy with who you are :)

Can I see a doctor to have x-rays on my growth plates to see if they closed up or not?