Hi there,

so, no. The activation date is what activates the Internet lines to your address and makes the service active. So if you plug in the equipment early, it just won’t work. Due to third party involvement as well, you cannot move the activation date. some more info can be found in the link. If you’re in dire need of Internet, I suggest you use your phones data if you have it, if you know someone who has Internet use theirs, or go somewhere that offers free wifi. 

https://www.koodomobile.com/en/help/ordering-online#