Liam you are in the beginning stages of puberty, unfortunately we can't predict or change the amount of time it takes to go through it or what the end results will be.
Your height and size may be a bit smaller than some your friends but a growth spurt can start at anytime.
Your concerns are part of growing up and you will continue to grow for a few years.
Accepting ourselves can be difficult but you are very close to the average height and size for your age.
Not sure what pinny is but being made fun of can really hurt and unfortunately many people target others for no reason. Try to avoid them and don't let them get to you they are just being jerks.
If things are real bad you could maybe talk to your school councillor.
You will get through all this and hopefully end up with the results you hope for.
Please try and remember that many of your friends and classmates are going through the same thing and have the same doubts as you do and it is all part of growing up.
Changes during puberty tend to be pretty slight and not very noticable but not not that long ago there was no hair and you were shorter and smaller, so it is slowly happening.
Try to accept and appreciate yourself the way you are, your height and size will change as you mature it just takes time.
Best of luck.
Your penis size is about right for your general body size. Both will grow when it's time. Some boys reach puberty (defined as the ability to squirt) at 9, others not till 14 or 15. You can expect a growth spurt soon, after which you may experience the joys of acne, shaving and embarrassing erections. (You can reduce the incidence of the last-named phenomenon by exercising the organ every night ;-) )