I have a best friend Luke, he is the one I admire. 
He is hard working and highly self-discipline. He is interested in many things, such as science, philosophy and langes. He is very involved in these things and has some unique views. 

Even he is only 19, but his understanding is far exceed the peers. He is good at encouraging people and help them when them met problems. Luke is happier when his friends are happy. Different habit makes him different in university. He always have a full day, but he combines study and life very well. It always makes him full of energy and keep positive. 

Luke has a pretty handsome appearance, tall and strong, and always kind to everyone. It is lucky thing to have such a friend.

I have a best friend named Luke, I admire him. 
He is hard working and highly self-disciplined. He is interested in many things, such as science, philosophy and languages. He is very involved in these topics and has a few unique / peculiar points of view. 

Even though he is only 19, his understanding exceeds his peers' by far. He is good at encouraging people and helping them when they face problems / challenges. Luke is happier when his friends are happy. He has to take up different habits when it comes to University. He always has a full day, but he manages to have a good balance between his school life and his personal life. It always gives him a lot of energy and keeps him in a positive mood. 

Luke is pretty handsome, tall, strong and is always kind to everyone. I'm lucky to have such a friend.

Hi Tracy, I'm a french guy, not a native english speaker, so I apologize in advance if my correction isn't perfect :)   Here some things I would rectify:
- Line 3 : not "langes" but "languages" (spelling mistake).
- Line 3 : "in these things" is correct I think. But you could say "in these topics" or "in these subjects"; maybe these words are more precise to qualify the domains that interest your friend.
- Line 5 : I'd say "Even though he is only 19 years old, his understanding is far superior to that of his peers."  (exceed is a verb and the expression "is exceed" is wrong I think).
- Line 6 : not "them met problems" but "they  met problems". And maybe the good tense for the verb would be "meet" and not "met"
- Line 7 : I imagine Luke as several habits. So I would say "Differents habits make him different in university"  (so I retire the 's' from make).
- Line 7 : "he always has" instead of "he always have"
- Line 9 : I think keep need an s, "he keeps positive", he remains positive, he stays positive

I have a best friend Luke, he is the one I admire. 
He is hard working and highly self-discipline. He is interested in many topics, such as science, philosophy and languages. He is very involved in these subjects and has some unique views. 

Even though he is only 19 years old, his understanding is far superior to that of his peers. He is good at encouraging people and help them when they meet problems. Luke is happier when his friends are happy. Differents habits make him a singular person in university. He always has a full day, but he combines study and life very well. It always makes him full of energy and he keeps positive. 

Luke has a pretty handsome appearance, tall and strong, and always kind to everyone. It is lucky thing to have such a friend.