Personally I would go with Avast as the first installation.
You don’t say which avast product you have previously installed (relating to your product key) ?
You should probably uninstall your old/previous installation of Avast or it might think you two installations of the product, if you only have a single installation license.
If a paid product, you should have a copy of your license/registration (product) key in your avast account when you install on the system. Link the new copy to your existing account.avast.com and that should effectively cover the new installation.
You ‘may’ have to remove the old system linkage to the avast product and old installation.
If you still have your email from when you purchased the product, that should have a copy of your license/product key.