[20/f] I need to get the courage to initiate the breakup with my SO [20/m], but I keep putting it off. Help?

I need some help. I need to initiate my breakup with my SO but I'm starting to stress myself out. I'm a coward. I need some motivation to just go do it, but I keep over thinking it. I already got some advice and I know I'm going to go through with breaking up, but how!? This will be totally out of the blue for him too, but it needs to happen, and its starting to feel like now or never. He lives close by, should I try and meet up with him outside one of our houses or should we go somewhere to talk? Inside our houses isn't an option due to parents. I can't keep putting hanging out with him off, I hate prolonging it and I'm sure he suspects something. Gah! This sucks. I feel sick to my stomach. What can I do to get up the courage? Please help. Thanks.

((if you want more to the story, you can check my post history, this is a throwaway account and that's the only thing I've posted/commented on))

tl;dr How do I make myself just go "do it" in regards to breaking up with my SO? The more I put it off the more my stomach seems to be tightening into a knot.