Maybe he's not such a bad guy, but I'm still bothered by the sex discussion. You are 15 and sex should be off the table at least until you become legal age. Even then you should not engage in sexual intercourse until you are ready to have a baby of your own.
I would tell him point blank that you are not ready for sex yet (and you are not despite what you may think) and if that is a deal breaker, then you are sorry. If he goes along, then maybe the relationship is worth pursuing. But either way, you need to be upfront with your parents and go by what they say.