hey don't worry about your size. If you look on the web about average penis size and learn about the structure of the vagina... you will see that size really does not matter. An average woman's vagina is only 4 in in length and for those men who are well endowed the vagina can expand 100%
Sorry but you are stuck with what you have, so learn to use it well. Size really does not matter if you know how to make it work.