Should I see if this works or move on?

I'm 15, and I like my friend's older brother who is 22. My friend doesn't know I like him though. Her older brother and I text eachother and flirt a bit but it is difficult to tell if he's into me or not. I'm not desperate for him but it would be nice if we can go out and have a relationship. He doesnt know or suspect i like him...well from what i think. He knows I think he's cute, so i don't really know if that really matters or not. My friends tell me that i should already confess to him that i like him but I dont know. So what advice would you give me?