"i am not that good at drawing but i want to becan i have some opinions on this drawing (if the scan works)and be brutal i have no sensitivity "
Honestly? The head's a bit small and the arms aren't even but it's a good start. The arms themselves are pretty good though. Keep trying.
Crit: You didn't draw the feet and lower legs. That's always a pretty big no-no. Yes, for panels and such, sometimes the legs get cut off. But it seems you just cut them off with plenty of paper space left. Drawing things we aren't good at helps us get better at them. Instead of shying away from lower legs and feet, you should just go for it.
One other thing, you have a large focus on contour and not so much the underlying shapes. But thats a big thing. I have no idea how old you are. That was a concept that took me a long time to try and hold on to.
last point. Draw bigger. Bigger paper, bigger characters. Get your whole arm into the drawing and that will help with everything. You can slide in more detail and stuff. Keep drawing. that's really the best thing artists can do. hope that helps dude.