What position should I play in rugby union, for people who know the game?

Ok basically, I've just turned 17 and am currently in my schools firsts team as a flanker. I'm 6ft1 and 85 kgs, after lots of weights work because I really wanted to play forwards this year after playing backs the rest of my life. I used to be very skinny and play fullback or wing and I was relatively quick. Im now doing good as a forward in my firsts team, but when I think about it my strengths arent pushing people around etc and my due to my bodyweight I've lost lots of stamina as my bodyshape now doesnt really suit my body. I look like a big man in a small boys body if that makes sense. Im quick and powerful now, have great ballskills definately not as quick in terms of reactions as I used to be, but my final question is what position do you guys after giving you that brief info will I suit in the future.