Starting structured football as a 16 year old

I am 16 year old and have been playing football since I was 13 I was one of the best player in school team but like there were very few good players and also there was no structured football in school and also was very good at dribbling(could easily dribble 3-4 players) and i played as a forward winger.

Recently(about 2 months ago)I joined the academy in my area after 4 months of break due to exams and stuff. Players here are very good so I found that my technical, shooting, passing, vision, dribbling, decision making and almost in every aspect of game I am weakest in team and also coach make us play 11 v 11 everyday and I don't feel that confident when I played in school with my friend and also they make me play defender sometimes LB and sometimes CB which I don't like I want to play winger but whenever I get the ball my mind goes blank I don't know what to do my body stand there and become static my vision blurs.

Now I want to improve in football so what should I do? how should I train? I want to become the best in the academy (Players have played at district and national level they are very good) and i have never even played district football in my life now I want to play as forward (my inspiration is messi and hazard)

So how do I train and improve fundamentals and become good?