Puberty and the changes that come with it are all part of growing up. Changes in the body and the brain can take some getting used to, and there are often lots of questions to be answered - teens and parents might be embarrassed to ask, and answer, but if you know where to look for information it can make these conversations easier.
It is best to be open and ask about anything you're not sure about or don't understand - that goes for parents as well as teens!
There is some brilliant information online - info for parents, info for young people about sex, FAQ's for boys and girls, puberty info from Radio 1, messageboards where you can ask anything you've been wondering about, info on periods and much more.
Everyone starts and finishes puberty at slightly different times, and changes happen at different speeds, so don't worry if you are different from a friend - that is normal. If you are a parent of a teenager you could look through some of the websites together and chat about what comes up, if you are a teenager it might help to look at the topics online, and show the information to mum and dad to start talking about these things - they'll probably be glad you asked, so they don't have to worry about what you do or don't understand!