Reading books is one of my hobbies, but very poor in comprehension

It might be because of your lack of concentration('reading from my young age' you said). Try to improve your concentration by meditation, yoga... Without thinking like this just try this and check whether it helps you. In my experience, concentration will do huge excellence in life..

Don't fret over it too much. There are really some sentence structures that will require some of us to read again before the author's thoughts start to sink in to us. You are not alone in this. When I was still in school, what I usually do is to list down all the words that make me confused about the statements. Then when I have learned what it means, I try to use that word as many times as I can within the day; be it for my papers or just chatting or texting friends. Hope this helps.

Just continue your passion on reading. If you want to learn the language you have to be comfortable with it. Read, ask, learn, and speak. Practice definitely makes everything perfect.

I think in each one's life may encounter this situation in reading, when there's a sentence I don't understand there's two way:one is to ask others for help,another is to neglect it, when I meet it another time in different context, I may guess the meaning.