How much bike are you getting? In my experience a competition geometry bike that is too big is going to uncomfortable and not handle right. I am just over 6' and 75" wingspan. I have always been faster on a 56 vs 58. At your age I don't know how much cash you have so I would look into used bikes spend 500 a piece on a 56 and a 58 and play around with fit and stem size. Then when you know what you like drop the big money later. Either way both would probably work.

I am able to reach far enough but too far put a lot of strain on my shoulder areas with the 58.

I think reach has more to do with torso length