You are so young. First off i agree with last answer you have to want it. Im not saying you dont, but its something to think about. 2nd , think about sex , fantasize as much as you need to before and during, you can keep these thoughts to yourself or share them. It is not that uncommon to only feel the pleasure outside. After he cums use that *** on outside and inside and then he will do it again. Sounds graphic. But if your not getting that wet,,use his. Eventually you will enjoy it more .
You may just have a very low sex drive. Clit stimulation is the only thing that really gets me off too, so you're not alone. You should talk to your boyfriend about this, and find ways for your sex to be mutually beneficial. You shouldn't have to be faking your orgasms all the time.
If you are just having sex to be obliging, it won't feel like much. There is probably nothing wrong with you, you're just having sex for the wrong reasons.