This requires immediate attention. If you think that you haven't achieved puberty yet means you are saying that you don't have any secondary sexual characters that is no pubic hair, no hair in the under arms, minimal or no beard or moustaches. Along with low weight and small height. If these are the problems your facing than you definitely need to visit an endocrinologist who'll examine you thoroughly and get some tests done. Specifically check for your testosterone levels. Do not ignore this and consult a doctor as soon as possible.