I have a crush and its quite a strong feeling..

My friend Jamie (straight BTW) who is about the same age as me ( I will be 18 soon also which is very exciting 5th august!) I used to know him from school and we didn't really hang out but recently we have been out a few times and are spending time together and it reminds me a lot of the times I spent with my ex girlfriend as we went to a quiet restaurant and were upstairs alone which was quite romantic and he liked it just like i did, saying it was really nice too. Also I never admit that I want it to be a date and just act casual about it with only the occasional joke about him (I don't want to let on that I think he is sexy as I've had very little experience with guys and I'm afraid I'll mess up) which overall is fun. But whenever I see him I have fantasies of kissing and cuddling and I think I should tell him I have a crush on him. But then again I am sure he is quite straight although he suggested we watch porn together which is a bit strange for a straight guy to ask. Any advice is good but the main thing is should I tell him I have a crush? I value my friends and I like to keep a small group I'm unsure if he would be ok with me finding him attractive, although he accepts my bisexuality very well, and asked me what I like and what I would try. I think he may be a bit curious too please help I'm so confused with him but I really wanna be with him