I am a boy who just turned 16 and can sing but can't really go high pitched PLEASE HELP!!?

i love to sing but i can't go high ptiched well i can but every time i am i fell like my voice is going to crack or i use my nose alot.. my voice has been cracking lateley.. is this because i am going through puberty and my high pitched voice will return when i am older..or i just can't go high pitched..and by high pitched i mean like bruno mars (gernade) and (just the way you are) i can sing most of the song good but when it comes to the chours i can't do it it feels like my throat is going to crack..PLEASE HELP!!