Please Help Me!!!!

my advice would be back off. i think you would want to value your friendship more. tell your friend about your feeling for dylan. if she really is your best friends, she would do the right thing and when dylan asks her out, she will turn him down no matter how much she likes him.
this stems down from a similar situation i had with 2 friends, i was the one fighting over the boy but obviously it tore their friendship apart.they are still friends but not so close.

Let them be. Let them date. You don't wanna lose your friendship over some boy you like.
And he'll probably say no if he likes Courtney.