Please keep this civil guys. Bare in mind this is a thread where somebody is asking for advice, not a debate thread.
Please respect OP and avoid bickering. If you want to debate the age of consent or age gaps you can do it in another section.
And OP, it's perfectly natural to be put off by his experience. You're quite different ages so he is likely to have had more action than you. If you want to continue this relationship then I would suggest you talk openly about bedroom activities and what each of you like and dislike. Most people have different bedroom experiences even if they are close in age so it's not a huge deal. You can learn what eachother like.
It is quite a big gap though (for this early in life at least) so you may find there are a few things you're at different pages on. It might be best to consider if this age gap is too big at the moment. That's something for you to decide though, not me or anybody else here.