worried about the foreskin

hi, im 16 and iv been recently just been retracting my foreskin and cleaning it, iv only just been retracting it for a couple of weeks (*strange i know) but one thing is, the foreskin seems to be stuck on the head so far wen i pull it back... is this normal? im pretty scared.. shouldnt go all the way til it goes behind the head?? and whats more is that wen its not erect, its very tight and it stays retracted.. wen it erect i am nervous to retract it because its very tight even on semi erect! how can i make it more flexible?? somebody please help, any information would be very apprecitated thanx