Cannot Upgrade From High Sierra

Hello,

I want to upgrade from High Sierra to the latest update as it is not longer supported with the release of Big Sur. I have looked in my available updates in the app store and nothing comes up. I have went to the link for the Big Sur Update on the app store and tried to open it but it still will not update. I hope for a solution to this problem as I will either need to upgrade or look into a new computer. I hope it is not the later.

I am running macOS High Sierra Version 10.13.6 on a Macbook Pro Retina 15 Inch Late 2013 model. I hope this helps and I thank you for any help you may provide!