Can te help me?

So... I'm in a musical. There is a REALLY cute, funny hot guy in it too. I have a HUGE crush on him. The problem is though is that I'm 13 and he is about 24. Plus I think he has a girlfriend who is also in the musical (unless she's his sister which I doubt). So I pretty much know that there is no chance we will ever be together. But the thought is heavy on my mind and I just want to get it off my chest to him that I have a crush on him, so he can think it's cute , and we can all sposta on. I'm still afraid to tell him though because what if it doesn't go how I plan? He has been a good friend to me and I don't want to ruin that. So should I tell him and get it off my chest o should I not tell him and just grieve over him for God knows how long? I really hate this. I wish I didn't like him but I do and I think the only way to put my mind at ease is to just tell him.