If you're as young as your thing says, 16 -you probably haven't peaked yet. If this is the case, I suggest to be patient because you will get there. Also keep in mind that everyone is different and maybe you just need a little more foreplay that you are getting. I suggest you start there- foreplay to help get you in the mood and patience (especially if you're only 16).
Also drugs -prescription medication and illegal can cut down your sex drive. Antidepressants are one of the best examples- many who use them feel a decrease in their sex drive. If you've started a new drug, it might go back to normal naturally. Wait a few months, if it doesn't then perhaps you should talk to your dr about switching meds.
There are also some health causes for a low sex drive. Depression is a big one. A under active thyroid could be another cause. If you feel that this lack of a sex drive is completely abnormal maybe you should talk to your dr about potential causes and get tested for diabetes, and thyroid problems. Make sure you ask for free t3 and t4 with the standard TSH as they are more reliable at saying what the thyroid is actually doing.
Are you on any form of birth control? Some birth controls may actually cause you to lose your sex drive.