Hello,
There is nothing to worry about as your penis size is completely normal. The normal penis size is 5.1 to 5.9 inches. You will not be having any intercourse difficulty but ensure to use a condom and have safe sex.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
Hello again. Don't worry, your size is quite normal. Buy regular-sized condoms (or get a male friend or your father to get them for you) and practice putting one on before your "big event". When you are in the "throes of passion" it can be easy to forget to put one on, but please, for both of your sakes, do so. You don't want to be a Dad at 15, and yes, she can get pregnant the first time. ;) ~MM